Springtrap

When this creature enters the battlefield, all
creatures with toughness 1 die.
At the beginning of your upkeep, if there are 4 or
more creatures with toughness 1 in all graveyards,
target creature with toughness 1 dies.
Once a brilliant mage, Wilhelm Afton's arrogance led
him to being stuck in the body of a beastly rabbit with an
appetite for small prey.