Dusk Phantasm

Flying
When Dusk Phantasm enters the stack, reveal it,
then put it face-down on the battlefield. Anytime
during an opponents' turn, you may pay {5}. If
you do, create an attack phase where only Dusk Phantasm can attack, and that opponent can
block as normal. Dusk Phantasm may still attack
as normal, if you do, turn it face-up until end of
turn.