Nergigante, Savage Extinction

Flying, menace
Rampage X — Where X is the number of +1/+1
counters on Nergigante (Whenever this creature
becomes blocked, it gets +X/+X until end of turn for
each creature blocking it beyond the first, where X is
the number of +1/+1 counters on Nergigante.)
At the beginning of your end step, you may pay
{b}{r}. If you do, put a +1/+1 counter on
Nergigante.