Undying Creature dies, its undying ability triggers, returning itself from your graveyard to the battlefield without a +1/+1 counter on it due to
Blightbeetle.
Resolve the
Evereth ability.
Repeat from step 2.
Notes
If you have a way to kill
Evereth and available, you can do so after putting a significant amount of +1/+1 counters on it to deal damage to each opponent using its second ability.
Results
Infinite +1/+1 counters on a creature.
Infinite creature ETB.
Infinite creature LTB.
Infinite creature sacrifice triggers.
Infinite death triggers.
Infinite damage.
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.