Card

Beacon of Immortality

Mana cost {5}{W}

Double target player's life total. Shuffle Beacon of Immortality into its owner's library.

Part of 26 known combos, 10 of them two-card. 3 official rulings.

Bracket

B1 Exhibition — Not in the same deck as its two-card combo partners: Vito, Thorn of the Dusk Rose, Sanguine Bond, Enduring Tenacity, Vizkopa Guildmage, Sorin of House Markov // Sorin, Ravenous Neonate, Tainted Remedy, The Archimandrite, False Cure, Plague Drone, Defiling Daemogoth
B2 Core — Not in the same deck as its two-card combo partners: Vito, Thorn of the Dusk Rose, Sanguine Bond, Enduring Tenacity, Vizkopa Guildmage, Sorin of House Markov // Sorin, Ravenous Neonate, Tainted Remedy, The Archimandrite, False Cure, Plague Drone, Defiling Daemogoth
B3 Upgraded — Not in the same deck as its early two-card combo partners: Vito, Thorn of the Dusk Rose, Sanguine Bond, Enduring Tenacity, Sorin of House Markov // Sorin, Ravenous Neonate, Tainted Remedy, The Archimandrite, Plague Drone
B4 Optimized — allowed: No restriction beyond the banned list
B5 cEDH — allowed: No restriction beyond the banned list

Two-card combo with Vito, Thorn of the Dusk Rose, Sanguine Bond, Enduring Tenacity, Vizkopa Guildmage, Sorin of House Markov // Sorin, Ravenous Neonate, Tainted Remedy, The Archimandrite, False Cure, Plague Drone, Defiling Daemogoth (early with Vito, Thorn of the Dusk Rose, Sanguine Bond, Enduring Tenacity, Sorin of House Markov // Sorin, Ravenous Neonate, Tainted Remedy, The Archimandrite, Plague Drone)

Bracket: Lotus Vault analysis, with Commander Spellbook flags

26 known combos, 10 of them two-card.

Vito, Thorn of the Dusk Rose + Beacon of Immortality
Produces: Near-infinite lifegain, Near-infinite lifeloss for target opponent
View on Commander Spellbook
Beacon of Immortality + Sanguine Bond
Produces: Target opponent loses the game
View on Commander Spellbook
Enduring Tenacity + Beacon of Immortality
Produces: Near-infinite lifegain, Near-infinite lifeloss for target opponent
View on Commander Spellbook

2007-07-15 · Wizards of the Coast
If a Beacon is countered or doesn’t resolve, it’s put into its owner’s graveyard, not shuffled into the library.
2007-07-15 · Wizards of the Coast
Beacon of Immortality’s effect counts as life gain (or life loss, if the life total was negative) for effects that trigger on or replace life gain (or life loss).
2007-02-01 · Wizards of the Coast
If you double a negative life total, you do the real math. A life total of -10 becomes -20.

Rulings: Scryfall · Wizards of the Coast