How can you create a combo with Garna, the Bloodflame, Gray Merchant of Asphodel, Sneak Attack, Phyrexian Altar?
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[START OF COMBO]This combo can be formed with Garna, the Bloodflame, Gray Merchant of Asphodel, Sneak Attack, Phyrexian Altar

Color identity: BR
Mana cost: {R} if Garna is in hand
Steps:
  1. If Garna is in the command zone, cast it by paying {3}{B}{R} and commander tax, if applicable.
  2. Otherwise, activate Sneak Attack by paying {R}, putting Garna from your hand onto the battlefield.
  3. Garna's enter the battlefield ability triggers.
  4. Holding priority, activate Phyrexian Altar by sacrificing Gray Merchant and Garna, adding {R}{R}.
  5. Resolve the Garna ability, returning all creature cards put in your graveyard this turn to your hand.
  6. Activate Sneak Attack by paying {R}, putting Gray Merchant from your hand onto the battlefield.
  7. Gray Merchant enters the battlefield, causing each opponent to lose life equal to your devotion to black, and causing you to gain life equal to the life lost this way.
  8. Activate Sneak Attack by paying {R}, putting Garna from your hand onto the battlefield.
  9. Repeat from step 3.[END OF COMBO STEPS]

Result:
  - Infinite death triggers
  - Infinite enters the battlefield
  - Infinite lifegain
  - Infinite lifegain triggers
  - Infinite lifeloss
  - Infinite leaves the battlefield
  - Infinite sacrifice triggers
  - Infinite storm count[END OF COMBO RESULT][END OF COMBO]

Other prerequisites:
  - Garna, the Bloodflame must be in your hand or in the command zone
  - Gray Merchant of Asphodel must be on the battlefield
  - Sneak Attack must be on the battlefield
  - Phyrexian Altar must be on the battlefield
  - {3}{B}{R} available if Garna is in the command zone plus enough mana to pay for commander tax, if applicable.
[END OF COMBO PREREQUISITES]
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