[RD/KP03] Killer Biteball

It’s a fish-eat-shark world.

Killer Biteball
Trap Card
[Requirement] When your opponent’s monster declares an attack.
[Effect] Until this end of this turn, all face-up monsters on your opponent’s field lose ATK equal to [the number of face-up monsters (Level 3 or lower/Fish-Type) on your field] x 300.
-Rush Duel-

Source.