Altyia, sliver shifter

Mighty commander — You can take cards of any colors in your deck if Altyia, sliver shifter is your commander.
When a sliver you control mutate, you gain 3 life.
Sliver spells you cast have mutate {x}, where {x} is equal to the spell mana cost (If you cast this
spell for its mutate cost, put it over or under tagret
non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)