Blitzcrank, Great Steam Golem

Blitzcrank, Great Steam Golem enters with a
charge counter.
At the beginning of your end step, put a charge counter on Blitzcrank, Great Steam Golem.
{t}: Blitzcrank, Great Steam Golem does X damage
to target creature an opponent controls, where X
is the number of charge counters on it. Then
remove a charge counter.