Houdini - (noun) An individual who pulls a disappearing act. (adj.) The act of "disappearing."
Everything seemed to be going great in the relationship, then Michael "pulled a Houdini" - meaning he simply disappeared. He stopped calling, texting, sending emails, visiting, etc.
It is what IMMATURE men and women do when they are no longer interested in pursuing a relationship with someone - very similar to children who "pull a Houdini" and disappear while walking through the department store with their mothers.