Toxapex

Those attacked by Toxapex's poison will suffer intense pain for three days and three nights. Post-recovery, there will be some aftereffects.

Poison Sting: Your opponent’s Active Pokémon is now Poisoned.

Venom Fever (50×): If your opponent’s Active Pokémon is Poisoned, this attack does 50 damage for each damage counter on that Pokémon.