Relentless Hydra

Relentless Hydra comes into play with twice X
+1/+1 counters on it.
Trample, vigilance, haste
Whenever Relentless Hydra attacks and survives
combat, remove a +1/+1 counter from it. You
get an additional combat phase after this one.
Only Relentless Hydra can attack during these
additional combat phases this way.