When this creature dies, mill three cards. (Put the top three cards of your library into your graveyard.)

Disturb {3}{U}{U} (You may cast this card from your graveyard transformed for its disturb cost.)

Flying

When this creature enters, you may shuffle up to three target cards from your graveyard into your library.

If Ghostly Castigator would be put into a graveyard from anywhere, exile it instead.