Yawgmoth by paying 1 life and sacrificing a creature, targeting any creature an opponent controls.
When the sacrificed creature dies,
Blood Artist triggers, causing you to gain 1 life and target opponent to lose 1 life.
Resolve the
Yawgmoth ability, putting a -1/-1 counter on a creature an opponent controls, and causing you to draw a card.
Hapatra triggers, creating a creature token.
Repeat.
Notes
You may also repeat this loop whenever a creature enters the battlefield under an opponent's control. The lock will end once you've drawn your library.
Results
Near-infinite -1/-1 counters.
Destroy all creatures opponents control.
Destroy each creature that enters the battlefield under an opponent's control.
Near-infinite card draw.
Near-infinite death triggers.
Near-infinite draw triggers.
Near-infinite creature ETB.
Near-infinite lifegain triggers.
Near-infinite lifeloss.
Near-infinite creature LTB.
Near-infinite creature sacrifice triggers.
Metadata
Lock
Bracket tag
SpicyBracket 3-4+
Probably 3 or 4, but hard to classify
1
2
3
4
5
1 · Exhibition5 · cEDH
Bracket tags are estimated from the cards and results of each combo, as a guideline rather than a strict classification.