This massive party was held on September 14th, 2012 after The Charmada War.
It consisted of the victors of the war, as well as a bunch of random people.
Halfway through the party, there were party-crashers: an Abra, and a Kadabra. They issued a challenge against the trainer named Brah.
This led to the partygoers dueling each other, in an attempt to prove who was the best trainer.
Official Events: Spooky Pokémon