Chimeric Egg

Whenever an opponent casts a nonartifact spell, put a charge counter on this artifact. Remove three charge counters from this artifact: This artifact becomes a 6/6 Construct artifact creature with trample until end of turn.

From Magic: The Gathering.

Open the interactive version on https://mythscribe.cloud/app/tcg/cards/cms6on7j9gxd1pb1hfvbz9vx9.