Railgunner, Forgotten Nomad

Whenever Railgunner, Forgotten Nomad deals damage, put two +1/+0 counter on it.

{t}, {r}: Raingunner, Forgotten Nomad deals 3 damage to target creature.

{t}, {r}{r}: Railgunner, Forgotten Nomad deals X
damage to target, where X is its power. Remove all
counters from Railgunner, Forgotten Nomad, it does
not untap during your next untap step.