Ironforged Bronco

When Ironforged Bronco enters the battlefield, flip 5 coins. For each flip you win, put a +1/+1 counter on Ironforged Bronco. Then, any player may have Ironforged Bronco deal X damage to them where X is Ironforged Bronco's power, if they do, sacrifice Ironforged Bronco.
"All the ferocity of a bucking bull harnessed into twenty tons of iron-plate fury!"
--Elesha, Hector's Muse