Sefris of the Hidden Ways + Radiant Solar + Spark Double + Chameleon, Master of Disguise

Prerequisites

• You have a way to cause a creature to enter the battlefield under your control.
• You are not currently venturing in a dungeon.

Steps

1. 1Put any nontoken creature onto the battlefield.
2. 2When the creature enters, Radiant Solar, Spark Double and Chameleon each trigger.
3. 3Resolve the Radiant Solar trigger, causing you to venture into Tomb of Annihilation and into the Trapped Entry room, causing each player to lose 1 life.
4. 4Resolve the Spark Double trigger, venturing into the Oubliette room, causing you to discard a card and then sacrifice Radiant Solar.
5. 5Resolve the Chameleon trigger, venturing into the Cradle of the Death God room, creating a 4/4 legendary The Atropal creature token and completing Tomb of Annihilation.
6. 6If you control two or more The Atropal tokens, put all but one into your graveyard due to the legend rule.
7. 7Sefris' second ability triggers, returning Radiant Solar from your graveyard to the battlefield.
8. 8Repeat from step 2.

Effects

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