Quicksilver Swampstrider

Mutate {1}{g/u}{g/u}(If you cast this spell for its mutate
cost, put it over or under target non-Human creature
you own. They mutate into the creature on top plus all abilities under it.).
———{line}{line}{line}{line}{line}{line}{line}{line}{line}{line}{line}{line}{line}{line}
Vigilance
Whenever this creature mutates, target creature
you control gets +0/+2 until end of turn.