D&D 5E Scariest Monster Ever

[TarionzCousin]

What is the scariest monster/encounter you have ever experienced?

Why was it so scary?

1. High Level Monster vs. Lower Level Party. "Run!"
2. Ambush! "They all get to go on the Surprise Round."
3. Reinforcements Arrive. "I think we can take th--Oh, crap."
4. Assassination Attempt. "Our cleric just collapsed in a pool of his own blood!"
5. Sudden Disappearance. "Hey, where did the Paladin and Fighter go all of a sudden?"
6. Conspicuously Weak/Innocent Monster/NPC. "Steve Buscemi in Con Air."*
7. Unseen Somethings. "They're picking us off, one by one!"
8. Little Girl Wandering Alone in a Bad Place. (Enough said.)
9. Nasty Trap. "What? This lever?"
10. Something Else! Please explain below.




* Edit: I realize Steve Buscemi's character in Con Air was a mass murderer and psycho. However, when all the other cons were posturing and showing how tough they were, he just sat there quietly. They were all scared of him.

 

[Nergal Pendragon]

Tarrasque with levels in the Bard class that favors Singing as it's use of the Perform skill.

 

[was]

Every time I have come up against a Behir in a campaign, like 4 or 5 times now, my character gets swallowed whole.

 

[TarionzCousin]

In one campaign I ran, I had a little girl be all alone out in the super scary woods. The PC's freaked out, certain that she was some sort of demon spawn undead hellion cheese beast. Two out of the five PC's wanted to run away and not even talk to her, leaving her to possibly die.

In actuality, she was a lost little girl with a valid reason for being there. The players were very reluctant to accept that.

 

[Ravenheart87]

Everything that petrifies.

 

[Stormonu]

"What the hell is that?"

Encounters where the party has NO IDEA what it is they are up against and, which by the looks of the creature, ought to be able to rip their faces off and defecate down their exposed throats. I've done it with encounters ranging in strength from goblins to ancient dragon-like entities, the most memorable being a white drake (normally about 8' long) that had an enlarge spell cast on it the first time they encountered it. The party retreated from it into a hall, and the thing used its fog breath on itself to obscure itself from ranged attacks and then dismissed the enlarge spell. When it barreled into the party in the smaller hall, they at first thought it was a different creature - perhaps its offspring.

 

[Raith5]

Ambushes are always bad news but ambushes involving Stirges are even worse. I know they are a simple monster but across the editions they have always given a headache when I played and a little bit of joy when I DM (in fact I like slurping loudly on my drink when they hit).

 

[PnPgamer]

Our group is highly suspicious of things the smaller they are and the higher level we are.

 

[Shiroiken]

Level Drain. Especially on Unholy Ground where the Cleric can't Turn Undead.

 

[Nebulous]

Fear of the unknown, coupled with CrEePy music, has always won out in our games. It's like the tension on an rollercoaster before you actually plunge down, that's the part that scares them.