Court Hussar
Creature — Vedalken Knight
Vigilance
When this creature 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 this creature enters, sacrifice it unless 
was spent to cast it.
Ron Spears
The List (PLST)
• #A25-51Rulings
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.
(wotc • 2006-05-01)
Rulings
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.
(wotc • 2006-05-01)