Nidoking (11/130) [Base Set 2]

[2G] Thrash (30+)
Flip a coin. If heads, this attack does 30 damage plus 10 more damage; if tails, this attack does 30 damage and Nidoking does 10 damage to itself.

[GGG] Toxic (20)
The Defending Pokemon is now Poisoned. It now takes 20 Poison damage instead of 10 after each player's turn (even if it was already Poisoned).