How can you create a combo with The Thirteenth Doctor, Crystalline Crawler, Gravecrawler, Altar of Dementia?
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[START OF COMBO]This combo can be formed with The Thirteenth Doctor, Crystalline Crawler, Gravecrawler, Altar of Dementia

Color identity: BGU
Mana cost: {B}
Steps:
  1. Activate Altar of Dementia by sacrificing Gravecrawler, causing target player to mill cards equal to Gravecrawler's power.
  2. Cast Gravecrawler from your graveyard by paying {B}.
  3. The Thirteenth Doctor's first ability triggers, putting a +1/+1 counter on Crystalline Crawler.
  4. Activate Crystalline Crawler's first ability by removing a +1/+1 counter from it, adding {B}.
  5. 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
  - Infinite storm count[END OF COMBO RESULT][END OF COMBO]

Other prerequisites:
  - All permanants must be on the battlefield
  - You control at least one additional Zombie.
[END OF COMBO PREREQUISITES]
assistant