Hydragon

Flying, Trample
Hydragon enters the battlefield with x head
counters on it. If this card would be destroyed,
remove a head counter from it then regenerate it.
Hydragon can attack or block additional times
equal to the number of head counters on it.
{r}{r}{t}: Deal x damage where x is
the number of head counters on this card plus 1.
{g}{5}: Put a head counter on Hydragon.