You will see the 5 scariest D&D monsters that my group and I encountered over the years. Disclaimer: If you are a player, this list will make you paranoid of dark lakes, simple CR 1/4 Zombies, ancient knowledge, dumping intelligence and NPCs in general. If you are a game master that uses these abominations, well, may the gods have mercy on your soul or better yet be on the side of your players when they encounter these creatures.
The Good, the Bad and the Sea Hag
You might think Mind Flayers and Fomorians are ugly monsters, but in comparison with the Sea Hag they are cuddly, cute and charming creatures. These Hags are the Olympic gold medalist in the sport of ugly, with a face like a dropped pie at a baking competition, with features that seem to have been arranged by a mischievous toddler with a box of Mr. Potato Head parts. Point is, they are so ugly that their look can kill you, literally! Even other kinds of Hags find them ugly beyond compare, and most likely admire them for it.
A One-Step Guide to Drowning your players
When I used a Sea Hag against my players, it was in an off corner of an underground, cavernous dungeon. There was a shallow dark lake there with a couple of narrow cracks in the cavern walls partially submerged in around 10 inch deep water. As my players slowly walked through the water, they spotted a creature starring from the distance trough one of the narrow slits. As soon as they saw its grotesque, horrific appearance and evil intend, initiative started. It won the initiative and duck to cover behind the crack. Everyone managed to put away their fear and disgust in order to dash towards it for 2 rounds, except the paladin of the group. He was consumed by fear, and his legs wouldn’t move closer to that thing. Third round. The Hag darts around the corner again and points a bony finger at the feared paladin, her eyes staring into his soul. Wis Save against her Death Glare. Fail. He drops to 0 Hit points. No big deal if he wouldn’t be in 10 inch deep water. He begins to drown. The healer tries to go back, but the Hag starts to attack with her disgusting claws. If the healer goes back, through the difficult terrain, the entire party is in danger, so he reluctantly stays. They manage to kill the Hag. But it is unfortunately too late for the Paladin.
6 Signs of ugly, single Sea Hags in your area
- One of the first signs is that some critters or animals appear in great abundance in the area. Like a village having a toad problem all of a sudden, leaving everyone puzzled at where they might be all coming from.
- Second one: these animals become increasingly hostile the closer you get to the Hags hideout. So if the Toads, Spiders, Snakes or the like that were docile a moment ago become aggressive, you might know that you are close to a sea hag.
- Thirdly, you find twigs, seashells, algae and other junk set up in mysterious patterns. If you spot the “Blair Witch Project”-Type stick figures, well, better split the party and go looking for the hag, preferably in the dark.
- There could also be a thin film of slime covering everything, like rocks on the shore. Slimy, slippery and a little sticky – awful.
- One hint could be very strong currents at sea or unusually high tides. Don’t fight her at high tide!
- And the most grotesque of all. A shore littered with dead and rotting fish, reeking for miles. This supernatural fish graveyard could turn the most hungry seagull vegetarian. And best of all, or rather worst of all, the hag knows if you poke or somehow handle the fish. She then uses it to speak to you – absolute nightmare fuel.
Conclusion: Sea Hag
So if you are using the Sea Hag, place her in a cave system with many narrow corridors and shallow water everywhere. She can phase trough walls if this is her lair. Which make her a formidable foe and also an annoying one too. Introduce yourself to the party with some hit-and-run tactics and get them to follow you. Try to separate them with the difficult terrain of the shallow water and try to get them to fear you. If you sense the suspense is at its height – death glare. Run in to finish the job.
Rot Grubs or: How I Learned to Start Worrying and Fear the Zombie
This one is very deceptively deadly. It involves the CR 1/2 Rot Grub Swarm and the CR 1/4 Zombie. Both of them are fairly easy to kill and have a hard time to do serious damage but when you combine them – oh man!
Where, What, Why
The What: The Rot Grub Swarm have the ability to instantly kill a character – or rather had… First introduced in Volo’s Guide to Monsters these critters had the ability to burrow into you and if you didn’t know about them then you wouldn’t know that you need to burn yourself in order to burn them out. If you didn’t, you died. They would eat themselves to your heart and then through it. But they got changed in the reprinting of Mordenkainen Presents: Monsters of the Multiverse and lost the ability to instantly kill you.
The Why: I think the change occurred because of the “if you didn’t know” part. If the players just failed the knowledge check, survival or nature I would suggest, then the infected player would just die. No recourse. No Save. Just dead. Revivified? The Worms are still there. DEAD again.
The Where: The Rot grubs are extremely slow and if you see them, truly easy to outplay. Emphasis on “If you see them”. Now to the really evil part. Rot grubs are normally found in corpses; zombies are moving corpses. You see where I am going with this? A rot grub infested zombie that somehow manages to wound you gets you infested with the rot grubs. You take little damage every round until you drop to 0 HP which outright kills you – no death saves for you, good day sir, I said good day!
Conclusion: Rot Grub Swarm
This monster(s) is a bit of a wild one. For one, the rules around this pest got changed, deservedly so. Also, one could argue that the grubs couldn’t just attach themselves to the wounds the zombies cause. Nonetheless, if your players find a worm infested zombie and know about these things, it wouldn’t be uncommon to see them flee from that CR 1/4 undead.
Knowledge is Power, but too much knowledge is Allip
Allips are undead that were most likely knowledge seekers in life. Successful knowledge seekers at that. But finding the knowledge and storing it safely in your noggin are, very much, separate things in D&D.
You don’t know the secrets of the Multiverse: Here’s why that’s a good thing
Adventurers like to know everything there is to know about the evils of the Multivers, for it is said that knowing is half the battle. Well, not so fast, my friend. You might find a tome containing the true name of Demogorgon or the hiding place of the phylactery of Acererak but reading it might just kill you! Potent knowledge can manifest themselves magically and infect your psyche, causing you to kill yourself. Unfortunately, it doesn’t just end there, but it might metamorph you into a dreaded Allip: a secret knowledge ghost.
Encountering an Allip and why they are far worse then Ghosts
Like a ghost, Allips can use hit-and-run tactics very effectively if they are in a walled area such as a library. They like to dwell somewhere where scribes can be found. Allips try to pass the knowledge onto others in order to be free of it and move on to the afterlife. Therefore, they torment innocent scribes with ancient knowledge nobody should know, driving them mad and maybe turning them into another Allip. In combat, they whisper part of the horrible secrets they obtained and causing visions and unbearable agony, forcing you to lash out at your friends. And if that isn’t enough, it can even stun your entire party with its abhorrent knowledge and cause major headaches. All in all, this thing is a powerhouse and even after it is defeated the party is left reeling with the glimpses of reality that the Allip spouted. Hopefully not enough of it sticks to the mind of the players, or they might find themselves turning into an Allip themselves.
Conclusion: Allip
An Allip is a great tool for any game master to make lore and exposition tasty for the players. Because, if the players have to work for it, they will be there for it. An exposition dump often leads to disinterested players because they didn’t work for it. But if they had to defeat an Allip in order to get glimpses into your world lore, you betcha they will dig deeper. Hopefully more carefully then the poor soul that turned to that Allip.
They like you only for your Brain: Intellect Devourers
These psychic brain puppies are no joke. Created by the devious mind flayers, these things can cause character death like nothing else. Especially if you are a barbarian or fighter (In my experience, the most likely classes to dump intelligence to 8).
What’s yours is mine
My party saw a mysterious, tentacled ship crash nearby and went to investigate (This was before Baldurs Gate 3 – I swear). On site there were these walking brains. The party discussed their strategy, while the barbarian wanted to climb a boulder for a better vantage point. On the boulder he saw an Intellect Devourer, under him, at the foot of the boulder. “I Rage, then I jump from this height on it, attacking with my axe!” – So he did, the other players were in shock, the Devourer died, the other Devourers noticed. Initiative. Some devourers zapped his Int away to stun him, and after the third or so, one managed to squeeze into his skull and instantly kill him. This was a high level party, mind you. But the combination of splitting the party and an abysmal int score killed the Barb.
Conclusion: Intellect Devourers
After that encounter, even the Intelligence based characters feared, or at least respected, the Intellect Devourers for their nasty abilities. If you want to use them, use them in packs. Maybe even in hosts if they had the time to procure them. That gives them a little more defenses till they stun and replace another brain. If you are really devious, you could give them spell casting hosts that have spells that can incapacitate players. But I’d advise against it, because it will feel very bad if someone dies just because of some bad dice rolls.
The many faced god: The Oblex
My players tend to shoot every chest they come across in a dungeon, “you’ll never know”. Years of D&D and Dark Souls have thought them to be mistrustful of Chest, “they might be something else”. The last, but definitely not least on this list of the scariest D&D monsters is the Oblex. Created by the Mind Flayers by experimenting on Oozes. These Oozes will give your party the same feeling as the Mimic did with an unattended, suspiciously inconspicuous, chest in a dungeon but with NPCs.
Put your players into the Truman Show
The Oblex can shape-shift parts of itself into NPCs that it scanned the brains off. Imitating them perfectly. Just a small hint of sulfur giving away its trick. Which can be, and will be with his high intelligence, masked with perfume or a good explanation for it. Like being a wizard with fireball components or a mine worker. The Oblex can then use its intellect to direct the party with near omniscience. Maybe making them get rid of annoyances like investigators or other adventurers, and afterward disposing them by luring them into the perfectly tailored trap for the party.
Conclusion: Oblex
This ooze is extremely dangerous on their own, but one might even combine them with their masters: the mind flayers to inflict maximum havoc. Not only random town NPCs, but even the loved ones from the party background, could be imitated by the Oblex for maximum psychological warfare. Even the lead designer of D&D, Jeremy Crawford, called these beasts one of the new scariest monsters. Just don’t overuse these if you don’t want your party to be suspicious of every NPC you throw at them, especially if they smell faintly of sulfur.
