Spurn Version 3.0

That title is a lie. There have been like six iterations of this mechanic before getting to this point. But I think we may be there. Would you play this creature?

I think this is the cleanest, most intuitive representation of the concept of spurn. If an opponent gets aggressive toward you during your turn, you can punish them. Like "reave," this incarnation of spurn can be keyed to trigger just once when casting a spell or when a creature comes into play, or repeatedly, as is the case with this gull.

The design challenge is keeping it focused on a punish response that fits for blue/white/green colors. And I think this mechanic is too complex for common. But that's okay. This is a reactive mechanic, not a synergy-focused one. You don't build your deck around using spurn. Each card stands or fails on its own.