Sarusan, The Galaxos

Flying, First Strike, Vigilance, Menace
At the beginning of your upkeep, exile the top
Card of your library, you may cast it for as long
As it remains exiled and mana of any color can
Be spent to cast those spells.
Whenever you cast a spell from exile, create a
Token that’s a copy of it, except the copy isn’t
Legendary. Sacrifice it at the beginning of the
Next end step.