Jeffrey & Friends' Adventures of Monsters vs. Aliens is a upcoming crossover to be made by tigerman531.
Jeffrey, Pikachu, Meowth, Nathan, Mitsuki, Batty Koda, Patch and Mushu meet Jeffrey's cousin Susan Murphy who suddenly gets hit by a metorite that makes her grow huge. Then the military arrives and captures Susan, Jeffrey and the others. They're brought to a top-secret secure facility where they meet four monsters: Dr. Cockroach, The Missing Link, B.O.B and Insectosaurus. Jeffrey also discovers a little infant girl named Xion. Together, Susan, her monster friends and our heroes must take on a alien invasion led by a alien named Gallaxhar.
- Baby Xion makes her first appearance in the series. At the end of the film, she gets adopted by Jeffrey.
- Susan is revealed to be Jeffrey's cousin.