Unknown Lair.
Inside the dark lair is a scarecrow-creature known mainly as the Summerween Trickster is talking to a group of 'people'. The one standing in front of the Trickster is Mitch the Enchanted Rhinoceros, the caretaker of the Easter bunnies and chickens. He went rogue after tiring of looking after them and sought to take over the Easter holiday. Thinking that instead of candy, kids should get useful things like batteries and socks on Easter. He puts it to the test with predictable results.
After losing his job he went into the black market, selling magic items that he stole from the bunnies and chickens as he still knew where all the magic items they used were kept. Which came in handy when the merge happened and all but passive magic went away. There are still some spell casting magic around like the magic from that city with the giant troll underneath it, the witches there can still use their brand of magic, but to use it you need to be able to calculate in your head to be able to use magic. As their magic is 'Formulaic Magic' sorcery is based on mathematics, many magic users who lost their magic couldn't handle the math needed to be able to use that brand of magic. A number of normal people whose jobs has them needing to know high level mathematics like accountants and actuary, learn how to use that brand of magic.
Mitch managed to make a name for himself in the underworld as a guy to call for magic items that work or could still be used. Like the stuff he took from the Easter bunnies and chickens. Which is why he's been called in to help set up a deal with Devour and a group he has gathered. And learning that Juniper Lee, the one who help stop him with his takeover of the Easter Holiday, he agreed to help. As the former caretaker of the Easter bunnies and chickens he has knowledge of holiday magic rituals and rules.
Mitch: "So, we're in an agreement? You are willing to allow us to use your power and do as we wish in your domain on your hallowed night?" He said which the Summerween Trickster nod.
Trickster: "Yes, I, the Summerween Trickster, allow it and so it may be done!" He said as a large flash of energy leaps from him and goes to the others in the room.
???: "Trick or Treat!" One of the mysterious figures said.
Gravity Falls.
Summerween is an annual holiday celebrated only in Gravity Falls, Oregon on June 22 or the second to last Friday of the month. It is celebrated because the residents of Gravity Falls love Halloween so much that they celebrate it twice a year. They use jack-o'-melons instead of jack-o-lanterns, since pumpkins are not ripe during the summer.
Seeing how only Gravity Falls celebrates Summerween, Sunset seeing dollar signs has set up a Summerween fair which has already gotten a crowd to come. She made sure to advertise the holiday through all the resorts she owns and having TV ads played in the local region. All to get people to come and spend their money at the fair. Sunset is already planning on having the holiday be celebrated in Equestria to draw in tourists and bring in holiday money.
For the kids who have just learned that there is a holiday that's like Halloween called Summerween that is celebrated in the nearby town of Gravity Falls. Many found it strange and wonder how the holiday even got started in the first place. But once they learned that there's free candy, they stopped caring and just enjoyed themselves.
Currently the Pines family is at a party store to get some stuff which is where Dipper met Twilight who told him what happened.
Apparently she felt remorse for what she and her former friends did to Rainbow Dash during the whole Mare-do-well. So she visited her and turns out it reveals a lot.
Rainbow Dash felt like she was betrayed by her friends as the humiliation that they did hurt her and apparently she didn't want to forgive them immediately but she swallowed her own pride and forgave them to keep her friends and suppose herd together.
