The Flunger

When The Flunger enters the battlefield, put a
flunge counter on The Flunger.
Riot — Whenever all creatures you control attack,
put a flunge counter on The Flunger.
Remove all flunge counters from The Flunger: Creatures you control get +X/+X until end of
turn, where X is the number of flunge counters removed. This ability costs 1/2 mana for each
flunge counter you remove.