Pale Wyrm Corpse

Sacrifices Pale Wyrm when it enters the battlefield,
sacrifice it unless its retrace cost was payed.

Whenever Pale Wyrm Corpse leaves the graveyard,
add {c}{c}{c}{c}.

Retrace (Discard a land card from your hand. you
may cast this spell from your graveyard by paying
its mana cost.)

Hexproof, Cascade, Cascade.