The travelling circus had quite a few different names. The Mystery Circus, the Carnival of Curiosity, the Terror Tent, among others. It traveled all over Oregon, and sometimes in the surrounding states.
The ringmaster was an old man by the name of Stan Pines. Most people thought he was rather shady, but they generally found the acts entertaining enough to ignore that. He also ran the sideshow, showcasing various "mystical artifacts" and taxidermied "cryptids", all of which were varying levels of obviously fake, though the crowds didn't mind.
The circus's strongman was a young man named Soos Ramirez. Despite being more hefty than muscular, he was pretty strong, able to lift a heavy weight and twirl it on his finger. He was also very kind-hearted, always willing to help out.
A red-haired teenager named Wendy Corduroy performed as an axe juggler and thrower. Despite her young age, she was quite skilled at her act, and often remained nonchalant as she was doing it.
A few years ago, two new performers had joined. They were Dipper and Mabel Pines, Stan's grandnephew and grandniece. Due to the two being twins, Stan first suggested that the two wear a large shirt and pretend to be Siamese twins. But when Mabel spied the big, colourful cannon in storage, her eyes twinkled like stars and she knew exactly what she wanted to do.
The cannon hadn't seen much use beforehand, though Wendy used it every once in a while, and there wasn't really a designated human cannonball. Mabel had fit perfectly into the role, and quickly became a favorite among the crowd.
Dipper, on the other hand, wasn't much of an attention seeker, and preferred not to be one to attract too much focus from the crowd. So, he decided to be part of Mabel's act, being the one to light her cannon's fuse.
Not much training or practice was needed for Dipper's part of the act, so he had a lot of time to read, as well as investigate the various places they traveled to. He ended up discovering multiple supernatural oddities, including land squids, gnomes, walking trees, and a windmill that made entire pizzas. He tried telling Stan about some of these, but he never seemed to believe him.
Dipper was now twelve, and his most recent discovery was a sparkling purple substance that he had been finding on the petals of flowers. He presumed that it was pixie dust, but he decided to take it back to the tent to study it a bit more. He collected a fair bit of it in a bag before heading back to the circus, where he absentmindedly set it down by a pile of other bags.
The next night, the circus put on another show. As Ringmaster Stan introduced the crowd to the first act, Dipper headed backstage to look for Mabel. He soon found her standing right next to her cannon, hastily wolfing down a funnel cake covered in cotton candy, apple crumble, and soft-serve ice cream.
She was wearing her human cannonball outfit, one she designed herself. It consisted of a glittery white suit with pink stripes that looked like a combination of a jumpsuit and a dress. Another piece of the outfit was a sparkly pink cape with a picture of a shooting star that she wore on her back. There was also a white and pink striped helmet on her head, with a glass visor. There was a spike at the top and a large curved horn on both sides, making the helmet somewhat resemble that of a viking. Her curly brown hair was more than long enough to stick out from underneath her helmet, and since joining the circus she had been growing it out, to the point where it now reached her ankles.
She turned to Dipper as he approached. "Oh, hey Dipper." she said between bites. "What's up?" she asked, sounding a little jittery and nervous.
"Our act's coming up pretty soon." said Dipper. "Uh, are you okay?"
"Of course I am!" said Mabel, pausing to take another bite. "It's just that I kinda eat when I'm nervous, and what's more nerve-racking than being shot out of a cannon? So I made this dessert out of a buncha circus food."
Dipper said "I mean, I can definitely get how being shot out of a cannon would make you nervous, it's stressful enough for me to be the one to fire you out, but you do it all the time. Aren't you kinda used to it by now?"
"Yeah, I do it all the time, and yeah, it's awesome." said Mabel, wiping her mouth. "But sometimes I think too much about it, and how I'm literally being fired out of a cannon, and what if something goes wrong and I get blasted into space, or blown to bits, and what if something bad also happens to you later on and I can't help you 'cause I'm in outer space?"
Mabel set down her dessert and abruptly gave Dipper a hug, saying "Bro-bro, if I get blasted off into outer space tonight, I just want you to know that everything's gonna be okay, and I'll be watching over you from the cosmos as you starry sister, and-"
"Mabel, are you feeling okay?" asked Dipper confusedly.
Mabel took a deep breath and said "Yeah. Sorry, I kinda mixed all the drinks from the soda fountain together and drank 'em. Again."
The twins spent the next few moments preparing for Mabel's act. Dipper tried to stay calm, though some of the things Mabel had said had started to put nervous thoughts in his own head. He almost always felt nervous during the act, considering he had to fire his sister out of a cannon in front of a large crowd, but it usually seemed to go well, and Mabel generally didn't get hurt worse than being covered in soot and maybe a bruise on her leg.
A short while had past before the twins heard Stan's voice from the center of the tent.
"Alright, I know that last axe got pretty close to that lady's head, but I'd just like you all to know that she'll get a free cotton candy on the way out if she promises not to sue us! Now give it up for our grand finale, Mabel, the human shooting star!" called Stan.
Soon after, Wendy walked backstage, carrying multiple axes of various sizes. "You two are up." she said as she walked past the twins.
Dipper said "Oh, I almost forgot to load in the gunpowder."
"Eh, it's fine. I already loaded it in myself." said Mabel. She quickly finished her dessert and climbed up into the cannon, taking a seat on the inner edge of the barrel. "I bet that new sparkly gunpowder's gonna be amazing."
Dipper took a deep breath as he looked up at his sister. "You sure you still want to do this?" he asked nervously.
"I sure do." said Mabel with a bright, braced smile. She pointed forward triumphantly and shouted "Onwards!"
Dipper nodded and pushed the cannon forwards for the show's grand finale.