"Tenth Edition", "end step" (2)
Trample, haste (This creature can deal excess combat damage to the player or planeswalker it's attacking. This creature can attack and as soon as it comes under your control.)
At the beginning of the end step, sacrifice Spark Elemental.
Haste (This creature can attack and as soon as it comes under your control.)
At the beginning of the end step, return Viashino Sandscout to its owner's hand. (Return it only if it's on the battlefield.)
Gatherer works better in the Companion app!
as soon as it comes under your control.)