Invader

undefined: An invader is a headmate that arrives in a system via system travel without the consent of the receiving system or the knowledge of the sending one.

This means that in the sending system, it's possible that the invading headmate never actually left. An invader is not necessarily hostile or unwelcome; it simply means nobody consented to this exchange.

Related Terms
System Travel refers to travel between two seperate systems in seperate bodies.