Phineas and Ferb Comic Reader: Quantum Boogaloo!

Phineas and Ferb need a tool that hasn't been invented yet, so they hop in a time machine and head 20 years into the future! Unfortunately, they're spotted by Future Candace, who follows them back in time to bust them on the day they built their giant rollercoaster. She does bust them—but by doing so, she changes the future!