As in, the kind of shit that would be fitting for legendary signatures.
I'll start:
>No Surprises
Ability:
When the user is active, all RNG is disabled. Moves never miss or crit, added effects never happen, and damage is fixed at 92.5% (the middle of the 85-100 range).
>Bullshit Room
Move:
Psychic
For 5 turns, all active Pokémon's stats are randomly shuffled. This means your HP could become your Attack, and any stat could become any other one.
>Blood Sacrifice
Move:
Dark
Choose two of the Pokémon in your party, and they will faint. Choose one enemy Pokémon (doesn't have to be active), and it will be KO'd.
>Shitstorm
Move:
Poison
Weather changes to Shitstorm for 5 turns (or 8 with Shitty Rock held). During this weather, every active Pokémon has a 20% chance each of getting confused, poisoned, or badly poisoned (60% total). Steel and Poison are immune to the poison, but not the confusion. It also damages non-Dark-types every turn.
>Penectomy
Move:
Steel
OHKO. 50 instead of 30 accuracy, but only works on males.
>Stall Breaker
Move:
Fighting/Physical
This move's power is equal to the number of turns that have elapsed in the battle.
>Overexertion
Ability:
The user is completely invincible for 5 turns, but cannot switch out, and faints once the turns have elapsed.