Umbral Leviathan

Delve ( Each card you exile from your graveyard
while casting this spell pays for {1})
Bestow {8}{u}{u} (If you cast this card for its bestow
cost, it's an Aura spell with enchant creature. It
becomes a creature again if it's not attached to a
creature.)
Enchanted creature gets +5/+5 and islandwalk.