Aether-Sphere

Whenever the player who controls this is dealt combat damage to by a creature controlled by another player, that player gains control of a number of Aether-Sphere's up to the number of creatures he controls that dealt combat damage (Even if that player is the boss, it if is, the attacking player will steal an Aether-Sphere from him for every attacking creature (because the Kaladesh-Boss never blocks but also can't take damage)).
Kaladesh-Boss