Forum:Waboku + Raiza

Hello,

I was wondering about this card interaction. My friend and I were playing. I summon Raiza targeting his face down trap card. He activates the face down card revealing Waboku. He said that it still goes on top of his library because it remains in the spell field and I say it goes to the graveyard because he responded to one of my effects.

Can someone help clarify this conundrum?

Thank you in advance,