Omniambivert

Someone who is both an Ambivert and Omnivert.

They are able to change between Introvert and Extrovert depending on the situation, requirements or to fit the mood.
They may involuntarily switch between being Introverted and Extroverted depending on their mood.

Steve: "Hey John, have you seen Bob?"
John: "Yeah, he's gone into Introvert mode, I wouldn't bother him right now."
Steve: "What happened?"
John: "Said he was bored and needed some alone time."
Steve: "Ah, ok gotcha."
John: "Such an Omniambivert!"
Steve: "I know right?"