Ashling, Shaman of Storms

Mutate {u/r}{u/r}{r/g}{r/g}
Trample, Haste, Prowess
If this creature isn't Mutated, at the beginning of the end step, sacrifice it.
Whenever this creature mutates, it gets +X/+X until end of turn, where X is the number of times this creature has Mutated.
Elemental Fusion {1}{u/r}{r}{r/g}