Containment Priest (Invocation) [Amonkhet Invocations] SV65 if you have no cards

if you have no cards in hand

Set: EX: Unseen Forces Type: Psychic Rarity: Holo Rare Retreat cost: Colorless

Destroy it at the beginning of the next end step if it didn't attack this turn

the player can activate mana abilities only if they're from lands that player controls and only if mana they produce is spent to activate other mana abilities of lands the player controls and/or to play that card

I'd have told you what it was

Containment Priest (Invocation) [Amonkhet Invocations] SV65 if you have no cardsSet: Amonkhet Invocations Type: Creature Human Cleric Rarity: Mythic Cost: {1}{W} Flash If a nontoken creature would enter the battlefield and it wasn't cast, exile it instead.