Urubonus, the Avatar of Malice

Monsters your opponent controls lose 300 ATK/DEF. You can only use each of the following effects of "Urubonus, the Avatar of Malice" once per turn. You can Tribute 1 Reptile monster; Special Summon this card from your hand. You can Tribute 1 monster; all monsters your opponent currently controls lose ATK/DEF equal to the original ATK of the Tributed monster, until the end of this turn.