Zombie

If you check the dictionary meaning of the word zombie.
The English word means : The Living Dead.
In terms of computer process it means :
On Unix and Unix-like computer operating systems, a zombie process or defunct process is a process that has completed execution but still has an entry in the process table, this entry being still needed to allow the process that started the zombie process to read its exit status. The term zombie process derives from the common definition of zombie—an undead person. In the term's colorful metaphor, the child process has died but has not yet been reaped.

That's what he is. He is alive just because he isnt dead. He has no expressions on his face, when he walks. When he talks, he talks just for the sake of talking, and never makes any sense.
He is alive(coming to office) just because his parent process(Super Boss) has not yet send him an exit signal(lay-off).

If you have seen him moving around in the office, you wont be scared when you see 1968 film, Night of the Living Dead.