Flameskull dies, it triggers, exiling it and the top card of your library with the ability to cast one from exile this turn.
Resolve the
Evereth ability.
Cast
Flameskull from exile by paying ({1} magic symbol) ({R} magic symbol) ({R} magic symbol) .
Prosper's second ability triggers, creating two Treasure tokens.
Activate the Treasures by tapping and sacrificing them, adding ({2} magic symbol) ({R} magic symbol) ({R} magic symbol) .
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
Exile your library.
Infinite +1/+1 counters on a creature.
Infinite Treasure tokens.
Infinite artifact ETB.
Infinite artifact LTB.
Infinite artifact sacrifice triggers.
Infinite artifact tokens.
Infinite colored mana.
Infinite creature ETB.
Infinite creature LTB.
Infinite creature sacrifice triggers.
Infinite death triggers.
Infinite storm count.
Infinite damage.
Metadata
In 2 decks according to EDHREC.
Bracket Tag
This combo has been estimated to be Exhibition (Bracket 1+).