Unesh, Criosphinx Sovereign [Hour of Devastation Prerelease Promos] Cat Beast you may petition to have

you may petition to have them returned

Set: Alara Reborn Type: Legendary Artifact Creature — Human Wizard Rarity: Mythic Cost: {2}{W}{U}{B} At the beginning of your upkeep

Rearm the Doom Citadel

Set: Eldritch Moon Prerelease Promos Type: Legendary Creature — Human Wizard Rarity: Mythic Cost: {2}{U}{B} When Gisa and Geralf enters the battlefield

If Cosmic Horror is destroyed this way

Unesh, Criosphinx Sovereign [Hour of Devastation Prerelease Promos] Cat Beast you may petition to haveSet: Hour of Devastation Prerelease Promos Type: Legendary Creature Sphinx Rarity: Mythic Cost: {4}{U}{U} Flying Sphinx spells you cast cost {2} less to cast. Whenever Unesh, Criosphinx Sovereign or another Sphinx enters the battlefield under your control, reveal the top four cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.