How can you create a combo with Feldon of the Third Path, Dockside Extortionist, Thornbite Staff, Altar of Dementia?
user
[START OF COMBO]This combo can be formed with Feldon of the Third Path, Dockside Extortionist, 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 Dockside Extortionist that is an artifact in addition to its other types.
  2. When Dockside Extortionist enters the battlefield, it triggers, creating at least four Treasure tokens.
  3. Activate three Treasures by tapping and sacrificing them, adding {2}{R}.
  4. Activate Altar of Dementia by sacrificing Dockside Extortionist.
  5. When Dockside Extortionist dies, Feldon triggers, untapping Feldon.
  6. Resolve the Altar of Dementia ability, causing target player to mill cards equal to Dockside Extortionist's power.
  7. Repeat.[END OF COMBO STEPS]

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

Other prerequisites:
  - Feldon of the Third Path must be on the battlefield
  - Dockside Extortionist 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.
  - Opponents control at least four artifacts and/or enchantments.
[END OF COMBO PREREQUISITES]
assistant