Muldrotha, the Gravetide + Wormfang Manta + Torpor Orb + Ashnod's Altar

Muldrotha, the Gravetide

Wormfang Manta

Torpor Orb

Ashnod's Altar

How it works

1. Activate Ashnod's Altar by sacrificing Wormfang Manta, adding CC.
2. When Wormfang Manta dies, its second ability triggers, causing you to take an extra turn after this one.
3. Cast Wormfang Manta by paying 5.
4. Wormfang Manta's first ability does not trigger when it enters the battlefield due to Torpor Orb.
5. Repeat each turn.

This clever setup achieves infinite turns by turning a drawback into an engine, cleverly bypassed by Torpor Orb so that Wormfang Manta's enters-the-battlefield trigger is neatly suppressed. Once the Manta is safely on the board, Ashnod's Altar steps in to sacrifice it for generic mana, immediately triggering its leaves-the-battlefield ability to grant you an extra turn. Finally, Muldrotha, the Gravetide lets you cast that very same Wormfang Manta right back out of your graveyard on each of your turns, locking down the game in an endless loop of recurring sacrifice and extra turns.