Its knuckle claws secrete a toxin so vile that even a scratch could prove fatal.
The toxin made in its poison sacs is pumped to the knuckle claws through tubes down its arms.
It has a poison sac at its throat. When it croaks, the stored poison is churned for greater potency.
Swaying and dodging the attacks of its foes, it weaves its flexible body in close, then lunges out with its poisonous claws.
The croaking that Toxicroak produces before a battle is for churning the poison it has stored in its poison sac.
— Pokédex entries (via PokeAPI)