Satya, Aetherflux Genius (Borderless - Ripple Foil)

Menace, haste

Whenever Satya attacks, create a tapped and attacking token that's a copy of up to one other target nontoken creature you control. You get {E}{E} (two energy counters). At the beginning of the next end step, sacrifice that token unless you pay an amount of {E} equal to its mana value.