Sonic X and Phineas and Ferb:Double Trouble Crossover
Status
Summary
Eggman has once again collected all 7 Chaos Emeralds, and Chaos Control is unleashed, but instead of going to Chris's world, it sends them to a whole new Earth, with different people that neither side knew existed. If there's people in this Earth that can help them return to Mobius, it's Phineas and Ferb.