Radiant Solar + Sefris of the Hidden Ways + Phantom Steed + Barrowin of Clan Undurr

Prerequisites

• You are currently venturing in Tomb of Annihilation in the Trapped Entry room.

Steps

1. 1Cast Phantom Steed by paying its mana cost.
2. 2When Phantom Steed enters, it and Radiant Solar trigger.
3. 3Resolve the Phantom Steed trigger, exiling Barrowin of Clan Undurr until Phantom Steed leaves the battlefield.
4. 4Resolve the Radiant Solar trigger, venturing into the Oubliette room, causing you to discard a card and then sacrifice Phantom Steed.
5. 5Phantom Steed leaves the battlefield, causing Barrowin of Clan Undurr to be returned to the battlefield from exile.
6. 6When Barrowin of Clan Undurr enters, it and Radiant Solar trigger.
7. 7Resolve the Barrowin of Clan Undurr trigger, venturing into the Cradle of the Death God room, creating a 4/4 legendary The Atropal creature token and completing Tomb of Annihilation.
8. 8If you control two or more The Atropal tokens, put all but one into your graveyard due to the legend rule.
9. 9Sefris' second ability triggers, returning Phantom Steed from your graveyard to the battlefield.
10. 10When Phantom Steed enters, it and Radiant Solar trigger.
11. 11Resolve the Phantom Steed trigger, exiling Barrowin of Clan Undurr until Phantom Steed leaves the battlefield.
12. 12Resolve the Radiant Solar trigger from step 10, venturing into Tomb of Annihilation and into the Trapped Entry room, causing each player to lose 1 life.
13. 13Resolve the Radiant Solar trigger from step 6, venturing into the Oubliette room, causing you to discard a card and then sacrifice Phantom Steed.
14. 14Repeat from step 5.

Effects

• Near-infinite death triggers
• Near-infinite ETB
• Near-infinite lifeloss for all players
• Near-infinite LTB
• Near-infinite sacrifice triggers