Template:Otheruses Mr. X (AKA: J'onn J'onzz or Marco Xavier) is a psychic hero who appears as a member of the JLX in Amalgam Comics.

Mr. X agreed to assist the JLX with their search for Atlantis in order to protect the mutants from the world that despises them. Mr. X used his psychic ability to direct the JLX in battle, and had particularly struck up a friendship with the Aqua-Mariner.

In a fight with Will Magnus in Atlantis (as Magnus had framed Aqua-Mariner for an attack on two oil tankers), it was learned that Mr. X was actually a Skrull who left Mars to try and find shelter from his own race. The JLX at first saw this as deception, but Aqua-Mariner pointed out that those who judge are judged themselves.

Mr. X is a fusion of Professor X of Marvel Comics and Martian Manhunter,and Mr X of DC Comics.