Runaway Steam-Kin 

Creature — Elemental
Whenever you cast a red spell, if this creature has fewer than three +1/+1 counters on it, put a +1/+1 counter on this creature.
Remove three +1/+1 counters from this creature: Add .
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL