Court Hussar

Vigilance
When Court Hussar enters, look at the top three cards of your library, then put one of them into your hand and the rest on the bottom of your library in any order.
When Court Hussar enters, sacrifice it unless {W} was spent to cast it.

The List

RNA Guild Kit

Vigilance
When Court Hussar enters the battlefield, look at the top three cards of your library, then put one of them into your hand and the rest on the bottom of your library in any order.
When Court Hussar enters the battlefield, sacrifice it unless {W} was spent to cast it.

Masters 25

Commander 2011

Magic Online Theme Decks

If this enters in a way other than announcing it as a spell, then the appropriate mana can't have been paid, and you'll have to sacrifice it.