Talk:Magma Field

This Field Spell's effect is clearly optional, not immediate, as Shark was able to activate the effects of two different cards (Bubble Bringer and Tripod Fish) before IV announce the Field Spell's effect.

There's just no way the monsters are immediately destroyed, otherwise the Field Spell's effect would kick in right away, right after Shark summoned Hammer Shark, instead of needing IV to "manually" declaring the effect.