You have had at least one Zombie enter the battlefield under your control this turn.
Steps
Activate
Evereth by sacrificing
Putrid Goblin.
When
Putrid Goblin dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
When
Putrid Goblin enters the battlefield,
Geralf's second ability triggers, putting a number of +1/+1 counters on it equal to the number of other Zombies that entered the battlefield under your cotnrol this turn.
Resolve the
Evereth ability.
Repeat.
Notes
If you have a way to kill
Evereth and ({1} magic symbol) ({BR} magic symbol) 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
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.