Rock Hydra

Rock Hydra enters the battlefield with X +1/+1 counters on it.
For each 1 damage that would be dealt to Rock
Hydra, if it has a +1/+1 counter on it, remove
a +1/+1 counter from it and prevent that 1 damage.
{r}: Prevent the next 1 damage that would be dealt
to Rock Hydra this turn.
{r}{r}{r}: Put a +1/+1 counter on Rock Hydra.
Activate this ability only during your upkeep.