Lithlek Hopper

Vigilance, reach
Escape {w/u}{w/u} ({w/u}{w/u}: Exile this creature. Return it to the battlefield tapped under your control at the beginning of the next end step.)
When Lithlek Hopper enters the battlefield, you may pay {w/u}{w/u}. If you do, Lithlek Hopper gains Flying until the beginning of your next end step.