I decided to make the first Phineas and Ferb and Star vs the Forces of Evil crossover. Hope you enjoy! Phineas and Ferb belong to Dan and Swampy, while Star and Marco belongs to Daron Nefcy.

Star was bored. Something she rarely is. She's usually bouncing up and down and ready to go dimension hopping or fight Ludo with her best friend. But today she just didn't know what to do.

"Hey Star!" Marco opened the door to Star's room with a smile plastered across his face. "So what do you wanna do today?" He sat on her bed next to her. Star sat up and groaned. "I have absolutely no idea." She said aggravatingly. Marco stood up. "Maybe we could do some dimension hopping. This boring old dimension has me bored. Plus I'm sick of school and fighting Ludo." Star nodded her head and sighed. "I guess." She picked up her scissors and cut open the fabric to a new dimension. "By any chance, do you know where we're going?" Marco asked worriedly. "Nope." She replied.

When they walked through the portal, Star and Marco found themselves In front of a yellow house. "Huh. Looks exactly like earth." Marco said confused. "I guess it's just another dimension like earth.." Star said. They walked up to the front door and gave a knock. With no response they looked inside the window. No one was home. "I guess no ones home?" Star shrugged. All of a sudden they both heard what sounded like screaming. They both looked at each other and ran to the fence of the backyard. They knocked and no one answered. Then the screaming was heard again. The source sound was coming from over their heads. When they looked up, they found what seemed to be a floating contraption.

"Hey! Is anyone up there?!" Marco yelled. Suddenly, 5 kids appeared, on hoverboards? Star tilted her head in confusion and Marco just looked with a shocked expression. "Look guys! Visitors!" Shouted one of the children. The child lowered his hoverboard with all of the others following his lead. When all of the kids came down, Star and Marco took a moment to study their appearances. The kid who came down first, was a surprisingly deformed child. He had a very pointy head, as of a triangle. Star made a surprised face and tried not to laugh. The next kid had an F shaped head. The three others seemed normal. Star and Marco decided to introduce themselves and stop staring. "Hi there! I'm Star Butterfly I'm a magical princess from another dimension, and this is my best friend Marco from earth!" She shouted gleefully. All of the kids cheered and welcomed her.

"Hi Star! I'm Phineas, and this is my brother, Ferb, along with my best friends Isabella, Baljeet, and Bufford!"

The triangle headed kid greeted. They all grinned and said "Hi." While Star was still greeting the kids, Marco looked at the hoverboards they had been using. "So what's this? Are you guys from the future or something?" Marco asked. "Actually," Phineas began, "these are hoverboards that we had decided to make today. We make crazy inventions everyday! We try to make the best of summer and come up with awesome ideas." Marco nodded. "That's so cool! So you're like, a kid genius!" "Well, my brother and I." He stated.

"Cool!" Star jumped with glee. "Could we use one?" She asked. "Sure! Just let me and Ferb construct one for you guys!" And that being said, both of the kids went straight to their work. Star and Marco decided to leave them to their work and talk to the other children. "So what do you guys do?" Star asked. "Well I don't really know. Me and my nerd just like to see what they come up with." Bufford said. "I like to see what creation the one and only Phineas Flynn comes up with." Isabella said dreamily. Star giggled. "Well that's so cool that you guys come to help them everyday and have fun!" Marco grinned.

Then, the door to the house burst open and a teenage girl with orange hair and a really long neck came busting out. "What are you two up to now?!" She growled. "And who are these two? Are they robots or something you created?" She poked both Star and Marco. They looked at her and had a confused look on their faces. "No actually that's Star Butterfly the intergalactic space princess and her best friend Marco!" Isabella said. "What? I've gone insane. I'm so telling mom. You guys are going to get busted!" She yelled.

"Who was that?" Marco asked. "Oh that's our sister Candace." Ferb stated. Star and Marco nodded. "Done!" Phineas said cheerfully. "Yay!" Star and Marco both chanted before jumping on the hoverboards. "Let us show you our cool arena we made for the hoverboards!" Phineas smiled. "Ok!" Star said. They all flew up to the arena and had an awesome time.

Time eventually flew by, and it was time for Star and Marco to head back home. "It was awesome seeing you guys!" Star said. "It was awesome seeing you guys too! Maybe you can come back and visit us one day!" Phineas and the gang said. "Bye!" Star and Marco both said before going into the portal to their home. Once they left, a beam shot the arena and the hoverboards Phineas and Ferb made, and shrunk them to where they were no longer visible. Not so long after, Candace brought her mom out to the backyard, only to once again find everything back to normal. "Again.." She sighed and went back into the house. "Who wants snacks?" Phineas and Ferb's mother announced. "Me!" They all said in sync.

Meanwhile, when Star and Marco got home, they talked about their awesome day, and went to sleep.

Well, hope you enjoyed. I'm glad I'm the first one for a PnF crossover! It was fun writing!