Boss's Chauffeur dies, its persist ability and second ability trigger.
Resolve the second trigger, creating a number of 1/1 Citizen creature tokens equal to the number of +1/+1 counters that were on
Boss's Chauffeur.
Resolve the persist trigger, returning
Boss's Chauffeur from your graveyard to the battlefield. It'll enter with a number of +1/+1 counters on it equal to the number of creatures you control minus 1 due to its replacement effect.
Resolve the
Altar of Dementia ability.
Repeat.
Results
Infinite +1/+1 counters on a creature.
Infinite creature ETB.
Infinite creature LTB.
Infinite creature tokens.
Infinite death triggers.
Infinite mill.
Infinite creature sacrifice triggers.
Infinite self-mill.
Metadata
Bracket tag
SpicyBracket 3-4+
Probably 3 or 4, but hard to classify
1
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5
1 · Exhibition5 · cEDH
Bracket tags are estimated from the cards and results of each combo, as a guideline rather than a strict classification.