Ghost (real name John Morley) is a Marvel Comics character that appears in Avengers Assemble and Spider-Man. Primarily a enemy of Iron Man, Ghost is a supervillain equipped with phasing technology who sometimes functions as a mercenary. He has run afoul of the Avengers multiple times, and in a scheme to steal F.R.I.D.A.Y., was beaten by the efforts of Ms. Marvel and Inferno.
A female version of Ghost will appear in Ant-Man and the Wasp, played by Hannah John-Kamen.
Ghost was a enemy of Iron Man's who had fought him several times in the past. However, after one of Ultron's failed schemes to destroy the world resulted in Terrigen Mists being released throughout the world, causing people with dormant Inhuman genes to undergo Terrigenesis and become Inhumans. It turned out that Morley was one of those many people, and upon emerging from the Terrigen cocoon, found that he had obtained actual phasing powers, no longer needing to do so with his tech.