After damage calculation, if this card battles an Effect Monster: Negate the effects of that monster (including in the Graveyard). You must control another face-up WATER monster to activate and to resolve this effect. If this card would be destroyed, you can destroy 1 face-up Level 3 or lower WATER monster you control instead.
Man when this card comes though for you it really freaking comes though. Just did a match agasint GBs where the big fusion card negating monster thought he was safe from WoD or whatever he thought I might have and just ended up down a card cause it killed this card a bit eariler.
TBH I wasn't completely sure about it and I believe it came though for me similarly before. (Vs Phoenix or neptheryths whatever you call it)