Elspeth, Storm Slayer (Ghostfire Halo Foil) is a White Mythic Rare from the Magic: the Gathering set Tarkir: Dragonstorm - MINT
Rules Text
If one or more tokens would be created under your control, twice that many of those tokens are created instead.
+1: Create a 1/1 white Soldier creature token.
0: Put a +1/+1 counter on each creature you control. Those creatures gain flying until your next turn.
−3: Destroy target creature an opponent controls with mana value 3 or greater.