How can you create a combo with Unlucky Witness, Mortuary, Phyrexian Altar?
user
[START OF COMBO]This combo can be formed with Unlucky Witness, Mortuary, Phyrexian Altar

Color identity: BR
Mana cost: 
Steps:
  1. Activate Phyrexian Altar by sacrificing Unlucky Witness, adding {R}.
  2. Unlucky Witness dies, triggering itself and Mortuary.
  3. Resolve the Mortuary trigger, putting Unlucky Witness on top of your library.
  4. Resolve the Unlucky Witness trigger, exiling the top two cards of your library.
  5. Cast Unlucky Witness from exile by paying {R}.
  6. Repeat.[END OF COMBO STEPS]

Result:
  - Exile your library
  - Infinite death triggers
  - Infinite enters the battlefield
  - Infinite leaves the battlefield
  - Infinite sacrifice triggers[END OF COMBO RESULT][END OF COMBO]

Other prerequisites:
  - All permanants must be on the battlefield
[END OF COMBO PREREQUISITES]
assistant