Genmu, Void Infinite Dragon

Mugen Climb 3 (You may cast this spell for {3} less
by tapping 3 permanents you control)
Flying
Creatures with Mugen Climb you control cannot take damage equal or less than X, where X equals their Mugen Climb value.
If a creature with Mugen Climb you control is destroyed, you can pay {u/b}{u/b}: untap X nonland permanents you control, where X equals the destroyed card's Mugen Climb value.