Ulamog, the Finite Gyre

When Ulamog, the Finite Gyre is cast, return target permanent to the battlefield.
Reanimator 4 (When this creature attacks, return 4 target permanents to the battlefield.)

Ulamog is indestructible.
When Ulamog is put into the graveyard from anywhere, its owner shuffles his or her graveyard into their library.