Reliant Protector

Reliant Protector is green.
When Reliant Protector enters the battlefield, you may put a -1/-1 counter on target creature you control. If you do, Reliant Protector gets +1/+0 and gains haste until end of turn.
At the beginning of your upkeep, if Reliant Protector is the only creature you control, you lose the game.