The Transmigration Prophecy [SDGU-EN037] Common Spell It does not have to

It does not have to activate its effects during the End Phase to shuffle itself into the Extra Deck

•Once per turn: You can Special Summon 1 Fiend-Type monster from your hand or from either Graveyard

Must be Special Summoned (from your hand) by sending 3 "Cubic" monsters you control to the Graveyard

3 or more: Each player sends 3 cards from their Extra Deck to the Graveyard

Once per turn (Quick Effect): You can target 1 Set Spell/Trap you control

The Transmigration Prophecy [SDGU-EN037] Common Spell It does not have toSet: Structure Deck: Gates of the Underworld Card type: Normal Trap Rarity: Common Attack: 0 Defense: 0 Target 2 cards from the Graveyard(s), shuffle those targets into the Deck(s).