Disinfector Gadget

Trample, menace
At the beginning of your upkeep, if an opponent controls a creature with a counter on it, Disinfector Gadget gets +2/+1 until end of turn and you unlock him. (Whenever a creature you control becomes unlocked, you may then use its unlock ability until end of turn.)
Unlock — {b}{g}: Put a -1/-1 counter on target creature.