How can you create a combo with Feldon of the Third Path, Priest of Urabrask, Thornbite Staff, Altar of Dementia?
user
[START OF COMBO]This combo can be formed with Feldon of the Third Path, Priest of Urabrask, Thornbite Staff, Altar of Dementia

Color identity: R
Mana cost: {2}{R}
Steps:
  1. Activate Feldon by paying {2}{R} and tapping it, creating a token copy of Priest of Urabrask that is an artifact in addition to its other types.
  2. When Priest of Urabrask enters the battlefield, it triggers, adding {R}{R}{R}.
  3. Activate Altar of Dementia by sacrificing Priest of Urabrask.
  4. When Priest of Urabrask dies, Feldon triggers, untapping Feldon.
  5. Resolve the Altar of Dementia ability, causing target player to mill cards equal to Priest of Urabrask' power.
  6. Repeat.[END OF COMBO STEPS]

Result:
  - Infinite death triggers
  - Infinite enters the battlefield
  - Infinite leaves the battlefield
  - Infinite mill
  - Infinite sacrifice triggers
  - Infinite self-mill[END OF COMBO RESULT][END OF COMBO]

Other prerequisites:
  - Feldon of the Third Path must be on the battlefield
  - Priest of Urabrask must be in the graveyard
  - Thornbite Staff must be on the battlefield
  - Altar of Dementia must be on the battlefield
  - Thornbite Staff attached to Feldon.
  - Feldon does not have summoning sickness.
[END OF COMBO PREREQUISITES]
assistant