Flying When you cast a spell, sacrifice Illusory Demon.
In the Maelstrom, a trick of the light can feast on human flesh.
Official Rulings for Illusory Demon
5/1/2009 : If you cast a spell, the spell goes on the stack, then Illusory Demon's triggered ability goes on the stack on top of it. The triggered ability will resolve (and you'll sacrifice Illusory Demon) before the spell resolves.