Kheru Mind-Eater

2017-08-25 If another player gains control of Kheru Mind-Eater, that player can see all of the exiled cards and may play them. Once a player looks at a face-down exiled card, that player may look at that card any time later in the game.
2017-08-25 Once you begin to cast an exiled card, losing control of Kheru Mind-Eater won't affect the spell.
2017-08-25 The last ability of Kheru Mind-Eater only lets you cast cards exiled by that card. If Kheru Mind-Eater leaves the battlefield, the exiled cards are lost forever.
2017-08-25 You may play land cards exiled with Kheru Mind-Eater only if you have an available land play this turn.
2017-08-25 You must pay the costs to cast the exiled cards. If one has an alternative cost, you may cast it for that cost instead.

Card is in preconstructed decks:

mtg.wtf