The Monster Possession Program is a program that Franz Hopper used the first time in the episode The Key. He used it to help Ulrich and Aelita to recover Aelita's missing fragment. He possessed two Mantas in order to get them closer to the glowing fragment. It allows the user to gain control over one or more monsters.

Jeremie hasn't used the program yet, probably because Franz maybe created it and the program isn't stored within the supercomputer.

During possession by the program, the monster glows a bright blue-white aura. The Franz-possessed Mantas were destroyed by falling blocks once Lyoko began to crumble. (The Key)