d100 Terrible things behind that dungeon door

So your players are getting sleepy as your roll the contents of that room they just kicked the door in. So you need some sudden violence. This is for my generic dungeon dimension influenced redbrick dungeons. Especially good for forced entries that might make things worse. Im not sure if this could be one dungeon but for some of those boring empty rooms or to amp up trouble then. 

d100 terrible things behind that dungeon door
01 Giant hungry toad ready to snatch and grab a humanoid and dive into its hole
02 Abandoned room with a fragile floor above a giant scorpion pit
03 A goblin ballistic team and four goblins in a shield wall guarding them, fire a shot then flee
04 Kobold with a cast iron grenade with a sparkling fuse and a happy grin
05 Goblins with a cart with eight single-use wooden barrelled guns and 4 operators, they are guarded by 4 hobgoblins with sword and shield. The gunner can fire once per round or all eight barrels at once. If the hit rolls under the barrels used the cart explodes inflicting a d4 per barrel on the goblins 
06 Owlbear on a chain held by a troll with a pitchfork
07 Room has steps down into a waist-deep water, a giant constrictor snake lives in the water
08 Room appears to have a checkered tile pattern, is an illusion into a pit of giant centipedes
09 Room with waist deep pit of bat guano and a swarm of panicked bats for a d6 rounds, local monsters all know about this door
10 A gibbet hanging in a small staone cell with a rotting adventurer corpse now animated as a moaning zombie inside. A sign left by dark elves reads: "Join Us Stay Forever"
11 Frightened youths in nightgowns look afraid. They are all hungry murderous doppelgangers 
12 A naked ogre is jiggling his fleshy rolls around in the mirror having just got out of the stone bath big enough for him. If he is killed and you look at the mirror save or become an ogre and are compelled to not leave the room. Only one person at a time can be the ogre. There is a fireplace and a hot teapot set out. If shattered behind the mirror is a treasure and a dead wizard
13 A strange sparkling mist is beyond the door that teleports anyone entering it to a deeper part of the dungeon that changes each day (you could reroll)
14 A round room with a plinth with a wand, a sword and a bow in the centre. One minute after the first person enters shutters drop over the doors and d4 1=snakes drop in through the roof 2=water pours in 3=ceiling lowers (1in4 with extra spikes) 4=trapdoor opens and an angry berserk minotaur comes out
15 A pool in a round room with a glass column in the middle with magic looking crown floating in it. The liquid with the crown becomes poison gas. The pool is home to four crocodiles that know to hide from the gas for ten minutes underwater. The crown can be a treasure, a curse or fake
16 High ceiling room has a wooden fortified wall in middle up to the ceiling with a strong barred door. The wall has many arrow slits for a dozen goblins led by a hobgoblin sergeant who has six special poisoned arrows for enemy bosses. They demand surrender or start shooting from their defences
17 A circular room with a thin circumference walkway around a pit with burning oil in the bottom. Most creatures don't know but a salamander lives in the bottom where people drown or burn
18 The door has an illusion of being solid, really is light pine sheets, inside the room is a pit with spikes and bones. An hour after the door and illusion broken a goblin comes back and installs a new door
19 Inside the door is a yawning great chasm with a crude rope bridge over the darkness, a doombat swoops at any who cross
20 Inside the door is a bridge over rapid water guarded by eight fish folk who throw javelins and then dive in the water. They may fight from the water or swim away
21 A magically dark room and inside lives a dire wolf used to fighting in darkness here. He may even talk or growl hidden by darkness 
22 A crypt with many burial niches, ghouls awaken and get out and stand screaming and hungry
23 Rapidly flowing stream wore through room, giant eels live here and take nips out of those passing through rather than leaping or climbing (1in4 chance of a d4 dead sheep with no guts in the water)
24 Small room full of gelatinous cubes each keen to get out of here
25 A bowl of gold coins in middle of small room, anyone touching coins releases a black pudding from a secret panel in the ceiling
26 The room is full of water and using the doorway is just like entering the surface of water. Getting to the other side is a bit of an effort for non-swimmers but there are also d4 1=shoal of man eating fish 2=four dogsharks 3=a giant crab or lobster 4=Marine wight pirate
27 Room bursts into flames for a d6 rounds as the first person crosses halfway point. d4 damage per round and lack of oxygen, once set off needs an hour to refuel
28 Gnolls with a ready one shot oil sprayer painted like a dragon and works like a large syringe, four other gnolls have spears and four more have millitary flails
29 Goblins throw diseases faeces then flee, any struck save or get d4 dungeon parasites, fungi or illnesses
30 Four evil dwarves and a evil priest have built tracks up to the door for a spiked battering ram they shove at who enters then throw hand axes, shoot a crossbow then mop up with Morningstar and shield  
31 A room packed with 20 zombies, if opened they swarm out and hunt and kill the living
32 Giant deathwatch beetle hiding among a pile of corpses makes its deadly call if disturbed
33 Shrieking fungus and giant crickets make a confusing racket. The crickets accidentally bounce off people who don't save and local creatures in the area all converge here
34 A wooden box with clucking from inside, a cockatrice
35 A frozen troll on a magic plinth of chilling. If shattered or broken many trolls will grow from the broken parts when they thaw out and the dungeon may be overrun with hungry mini-trolls
36 A pool of dungeon effluent with a Neo Otyg relaxing and eating poop. Will offer to trade sewer pearls for corpses
37 A slimy sinkhole into a deep cavern full of streams, fungus and giant bugs
38 Floor has collapsed and corpses piled here, rot grubs in bodies can easily be contacted
39 Illusion of room with chest, actually a slippery pit of green slime
40 Goblins enjoying a open pit fire with several adventurers impaled on spits over fire while hungry smiling goblins lick their lipw with delight (possible adventurers you met in a pub once)
41 Robed old women around an altar with wands on it. The women are rude and cranky and warn you to go away, they are really wereravens who worship a dark godess and happy to eat intruders
42 A man chained up with magical manacles begging for freedom. If the lock is picked the shapeshifting dampening power of the manacles allows him to turn into a were panther 
43 Seven dwarves dance around a tied elf maiden who is weeping. They demand treasure for the elf who is really a doppelganger and leader who will betray the party and leave pebbles for dwarves to follow
44 Room is full of orc babies in cots sucking on turnips. A human paladin wanabe has just arrived and has his sword ready to end these potentially evil babies, he has several white hooded priests encouraging him. They are a puritanical racist sect unpopular with everyone
45 Room is a cell with a dozen badly wounded torture victims and hostages who all need urgent medical aid and food or they will die  
46 A bugbear nanny nursing several baby goblins will throw her babies at adventurers and run calling for help to local monsters (possibly goblinoid parents)
47 Fourty kobold berserker warriors are meditating on pure rage in silence and are very mad if interrupted. One of them if a hero and son of a vindictive kobold deity
48 A squid folk wizard surrounded by hoard of degenerae blind mutant servitors sniffing while while the master is starting to saw open an awake bound prisoners skull
49 Child ogres as tough as orcs with clubs very exited to get a real fight. Their mother is a night hag and their father is a great ogre warlord who will ask his god who killed his heir
50 A flooded sinkhole in the floor where fish folk priests are dragging white robed youths into the water. As each is dunked their hybrid fish characteristics and knowledge of fish power of the ancients awakens in them. Any saved from this fate requires strange magical help or a life without children as they carry thy fish hybrid taint. Better still one could gain a romantic link to a character
51 A band of goblins led by priests are passing around human and baby goblins around and some swap species as they do like some sleight of hand trick. The goblins do this to replace sickly and weak babies and send the rejects to human homes to usually die without propper goblin fruits and food 
52 Friendly drinking goblins say its too nice a day to fight and offer you goblin shroom beer and fermented wolf milk and other exiting goblin drugs. They are also selling weird cursed items at low low prices. Any who eat their delicious fruit must save or is adicted and will find their way back to goblins a willing slave in fairyland forever 
53 Goblins are sculpting humanoid piles of feces with arcane goblin glyphs, on command of the priest the feacal golems attack and the goblins flee. Only petty but they also carry the plague
54 The room has ghasts and ghouls inside, once open their stench pours out and the screaming monsters charge
55 Troglodytes having a bath, They have been poluting this pool with their musk and poop for months. The door smells bad and any opening it are hit by trog stench. Anyony touching the water or worse splashed with stink of trog for 3d6 hours and will require a saving throw every ten minutes or succumb to the smell and lose 1hp vomiting. Some trogs might throw buckets of water as they flee
56 Room is where smoke from various chambers is brought to by vents with a chimney to higher up somewhere. The room is flooded with choking smoke and booby traps around a filthy narrow pit  
57 Circular stone room with well partially capped by tilted basault stone disk. The gibbering mouther within turns stone into mush around the well then starts screaming alerting local monsters while attacking 
58 Chaos goat folk warriors leap to attack, several in the back throw gourds of stinking goat folk pee at enemies. Any splattered failing a save will attract more goat folk till properly cleaned up with soap (no bathhouse will let you in) 
59 A giant fungus chamber and in the biggest shroom is a lovely mushroom dryad who has a few goblin youths with her that will attack romantic rivals to the death. She of course requires new lovers for a few months or will release people if given worthy replacements
60 Long ago a baby giant snapping turtle came in here and ate some people and couldn't get out. Now it can barley turn and will snap through open doorways. Monsters know to throw a corpse in one way then pass it the other way quickly
61 Long chamber with foot wide holes in stone at ankle height. Giant angry constrictor snakes live in the well and can nip through the holes or grab a leg with their body while partly covered or can easily slide out to finish a victim to eat
62 Long flooded chamber with holes in walls where something burrowed in. Young giant todas hide in flooded rubble and holes
63 Room has a cage of rabid berserk baboons with barley enough room to pass without being grabbed but may cop some thrown poop. When halfway through the room four cage doors and a hatch in the cage roof opens allowing them to swarm out from all directions and trap intruders between walls and cage
64 Pit of lava with an illusionary bridge over it. An unencumbered athlete might jump over. Fire toads swimming shoot fire at anyone crossing
65 Room with swinging pendulums over a walkway, if knocked of the walkway fall into pit with flesh eating apes. The apes have learned throwing bones at people trying to cross the walkway distracts them
66 This room has a magical wonderous clean toilet and a goblin footman with mushroom skin paper on a roll and a toilet prush he uses to wipe for anyone. He is cursed and not afraid of death and knows lots of monster gossip. The room is scented of pine and has soft relaxing harpsichord fugues playing. Their is a separate well and bucket of good water and soap bars
67 Monster bathhouse where goblinoids, orcs and an ogre with a few pet wolves and giant rats are having a bath. Goblin attendants with brushed on poles clean the seated naked monsters. The monsters ask you to go away or come back later. They all have weapons on hand but armour is on shelves by entry
68 Room has ornate stone artwork and four grinning gargoyles hiding in open
69 The room is made of living pulsing flesh and slime. Any who enter or try to look at the gelitinised bones in the slime will have ochre jellies form and attack them like antibodies
70 A mad unicorn is trapped in here. It is possessed by a ghost and seems insane but could be saved. Lets hope people figure that out before they get brutally stabbed. It says very un unicorn stuff and talks about this new body to give clues to thick adventurers
71 Their are four barrels and each has a coin on top. If touched the barells split releasing terrified flumphs who have been mistreated and release skink and lash out at any they assume are enemies squealing and sobbing the whole time. Releasing other barrels is easy with those tentacles
72 A nasty sprite and his gang hide in the room to render people helpless then tie them up and watch monsters eat them. Local monsters know to follow sprites to a feed so if battle goes poorly they scatter and each bring back a new hungry monster. In the room are draws full of dungeon invoices the boss treasury is missing. Under the chest of draws is the sprites home with tiny clothes, furniture and doll house size household goods worth good money
73 A gang of four imps in here three remain invisible one turns into a lost puppy. The gang live to play tricks and slip contracts for their souls in return for gold. The offers get more tempting and strange things happen around the party due to secret imp trouble
74 Gremilins and their pet rats live among a trash heap in the room. The rats will swarm attack then, gremlins riding giant rats will attack with poison darts with paralasys poison save or held for ten minutes. When they get prisoners they will check for were rats to kill first the rest they will eat
75 A crystal orb on a plinth, hard to shatter but possible AC+10 HP100. Detects as magic and evil. It is used by a distant evil boss and if damaged he will send a section of orc commandoes to attack the vandals family, loved ones or property
76 Doppellganger with a wand of illusions - will use ESP on adventurers and then create illusions from a hidden ceiling pannel. Especially likes to dredge up fears and loved ones in hopes of making adventurers give up. If detected will turn into a halfling and pretend was cursed and didn't mean harm
77 Twelve orc hopolites trained in shield wall and have +2AC in formation while three in the back throw javelins. A famous orc hero leads them
78 Horrible fleshy tree with living birdhouse in branches, gives birth to stirges, It has 2d4+4 and makes a new stirge per round in combat until killed (AC+4 HP30)
79 Ossiary chamber lined with bones, if intruders touch any of the alter candlestick holders or cause damage 2d6 skeletons rain from the roof and walls up to 40 untin the intruders die or flee or skeletons killed. Those currently moving and fighting will chase any who flee to return if they win
80 Monster hospital, a goblin shaman and a dark elf priestess aid various wounded monsters and send hero types for renewal at a proper temple with raise dead. Their are 4d4 patients, and a d6 goblin apprentice healers. There are a d4 preserved hero corpses. They will demand the right to keep working. They send rescue zombies to bring back wounded here
81 Pool for a Nymph with her pet giant eel and six blind fish folk warrior monks. She will be having a meal and will threaten intruders and demand repairs to the door and compensation for making her mad. She will drop her robe to kill any who see her in combat and use her magical abilities or take the form of a constrictor like serpent or water
82 Room surrounded by mirrors with a shiny sword held by a trapped plinth (save of d8+trap arm required 40 STR total to open). When the trap is released a mirror shatters revealing a basilisk
83 Evil black cap brownies are making a crying child dance but will flee into secret trap doors leaving the child if caught out. The child has been missing for 80 years and wants to go home. The brownies left a iny keg of mushroom beer good for one drink that gives you detect magic for one hour
84 An old woman is stuck in a complex looking trap clamping her leg. She is a doppelganger and the trap her mimic friend
85 Zombie beavers have damned the room with a wall of human corpse parts to hold a pond of rotting blood. Giant flies and maggots splash about and will protect the dam and the beavers. Any who fall gets dragged into the dam wall by zombie beavers
86 A savage dungeon dwelling vampire walrus lives here but he no longer craves fish. He keeps a selkie maiden in a cage
87 Shape shifting rat spirit folk pretending to be tomb robbers. Will offer to work together or share maps. They will give false information and try to come with you. They all are sneaky like thieves and know unholy spells. They might follow and send scouts ahead to warn monsters
88 A box in the room with a bell next to it moves when you come near it. Inside are 30 undead severed hands that pour out to attack, one will ring the bell attracting local monsters 
89 Walls and floor are covered in yellow mould and an illusion that makes it seem a boring room with several doors
90 A second door on inside can only open when first one closed so only a few warriors can fit at a time and pass through. Once on the main room there is a room with fake doors and intricate stone carvings. At some point when the first few are inside the doors slam and bolt shut and the statues attack. Once those in room are dealt with they can open the door to get at people trapped between doors then will move onto the rest
91 Zombie goats charge out butting people over and trampling them then biting
92 Crypt Keeper seated on a throne behind a force wall starts teleporting enemies
93 Floor is an illusion, any stepping on it hits a slide and drops to a lower level, if any climb back up the passage seals and dumps water down the slide to clean it
94 Floor of chamber is covered by slime and maggots, unfortunately there are pits you can sink and drown in if you fall in them
95 Chamber with large flower beds under magic lamps, each bed has a different carniverous plant. If you dig in soil among roots you find bones and damages items, some magic ones survive
96 A dank filth covered garbage pit with shafts where other areas dump waste. The once square room is now coated in gunge. The lowest part of the pit is water and hair choked bars. Anyone in here long attracts 42 giant rats from the drain system. If half killed the rest flee
97 A small round chamber with a demon imprisonment sigil around the room, entering crosses the border and a lesser demon appears to slay the person who called it here
98 A chamber with four elemental shrines. Intruders in the room call a small elemental - usually is all four same it is the same element or random if all four elements present in shrines

99 Four diabolic sigils are on the floor, if any non LE being crosses the room four abishi devils appear and demand your souls signed for now or be killed 
100 A minor great old one or a dangerous minion is imprisoned inside the warded chamber, the creature is difficult to permanently kill for long