Eternal Scourge

You may cast Eternal Scourge from exile.
When Eternal Scourge becomes the target of a spell or ability an opponent controls, exile Eternal Scourge.

Food Chain

Exile a creature you control: Add X mana of any one color, where X is 1 plus the exiled creature's mana value. Spend this mana only to cast creature spells.

Misthollow Griffin

Flying
You may cast Misthollow Griffin from exile.

Squee, the Immortal

You may cast Squee, the Immortal from your graveyard or from exile.