Boss idea-

New idea dice gobl8n any attack if gets a bad roll self harm and doesn't use the attack again

explain pls

Bristle does not attack directly, instead he likes to sabotage the one thing you think is safe.

ahh, so like he might replace a party members bag of holding with a bag of devouring while they sleep

no, he doesn't do that. Clue- What is a bristle?

bristle
noun
a short, stiff hair on an animal's skin or a man's face.

Alright I'll tell you. Bristle somehow has become aware that he is in a game, and is able to literally sabotage the dice that you roll.

so weighted dice, but for 1's instead of 20's

yeah, he's able to make it so that high=failure and low=success. He's also able to curse Weapon and Spell slots. He even attacks during your turn. Overall, he's pretty impatient.

so a PC, but an boss

yeah.

ok so how do you plan to run it

wut.