The Magma Worm is the final boss in Code Lyoko: Quest of Infinity and will be in the Volcano Replika. After the player completed the way through the Volcano Replika, Ulrich and Yumi will fight William while Aelita and Odd will fight the Magma Worm. The Magma Worm has three phrases, the first one is that monsters come out of it to fight Odd or Aelita and then, Odd and Aelita have to run around him to shoot on his back while lava will follow them from behind. The second phrase is that he will stand up and four tentacles will come out of it and Odd or Aelita need to shoot on the tentacles to defeat its second phrase. However, when they defeated one tentacle, falling rocks and lava will try to attack them, so they will need to run on the rocks in the lava and run quickly back on the rocks. The third and last phrase is that the Magma Worm will summon some monsters to attack you and will attack too. There will be a red mark on his body and that is where Odd or Aelita need to shoot. After that, the Magma Worm is defeated and William is freed by process because the Volcano Replika was destroyed and Jeremie used a code that will free William once they destroyed it.