The Futurama/Simpsons Infinitely Secret Crossover Crisis

Summary

Fry is reading an old simpsons comic and he tells everyone that they are taking the biggest comic collection in the universe to the planet, where it will be sealed in liquid diamond forever, as this is apparently the only way they will be true collectibles. The brain spawn the return and traps them within the simpsons universe with amnesia where each futurama characters encounter a simpson character.