Canker Abomination enters the battlefield, it triggers, putting a number of -1/-1 counters on it equal to the number of creatures an opponent controls.
Canker Abomination dies as a state-based action due to having 0 or less toughness, triggering its undying ability, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
Repeat from step 2.
Results
Infinite creature LTB.
Infinite creature ETB.
Infinite death triggers.
Metadata
Bracket tag
ExhibitionBracket 1+
For any deck
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.