Elder Oblex

As Elder Oblex enters the battlefield, it becomes
an enchantment Aura Curse attached to target opponent with "At the beginning of enchanted
player's upkeep, exile the top three cards of their library."
{u}{u}{r}, Put target creature card exiled by
Elder Oblex into its owner's graveyard: Elder
Oblex becomes a copy of that creature. (It is no
longer an enchantment Aura Curse attached to a
player.)