Togglodyte 
Artifact Creature — Golem
This creature enters turned on. Whenever a player casts a spell, toggle this creature's ON/OFF switch. As long as this creature is turned off, it can't attack or block, and prevent all damage it would deal.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyNOT LEGALvintageNOT LEGALcommanderNOT LEGAL