Togglodyte

Artifact Creature - Golem
Togglodyte comes into play turned on. <CR>
Whenever a player plays a spell, toggle Togglodyte's ON/OFF switch. <CR>
As long as Togglodyte is turned off, it can't attack or block, and all damage it would deal is prevented.

Artifact Creature - Golem
Togglodyte enters the battlefield turned on. <CR>
Whenever a player casts a spell, toggle Togglodyte's ON/OFF switch. <CR>
As long as Togglodyte is turned off, it can't attack or block, and prevent all damage it would deal.