zombies

zombie

1. Literally, a corpse, usually human, that has been reanimated from the dead, especially one that ambles around mindlessly attacking or eating people. Often used as a modifier. In the story, he uses the genie's wish to bring his dead wife back to life, only to discover that she returns as a zombie. Like so many other zombie films, some unspecified virus spreads across the world, bringing the dead back to life.
2. By extension, someone who functions in a robotic or automatic manner, especially due to physical or mental fatigue. I was up all night dealing with two sick kids, so I've been a bit of a zombie in the office today. The work is so monotonous and repetitive that you turn into a bit of a zombie by the end of the day.

zombie out

To function or behave in a listless, vacant, or robotic manner. An allusion to the characteristics typical of a zombie, a reanimated human corpse that shambles around mindlessly. I was up all night dealing with two sick kids, so I've been zombying out in the office today. You can't help but zombie out when you're doing such boring, menial tasks. My dad just sort of zombied out after my mother passed away.
See also: out, zombie
Farlex Dictionary of Idioms.

zombie

(ˈzɑmbi)
1. n. a weird and frightening person. Martin is practically a zombie. Doesn’t he ever go out—in the daylight, I mean? Britney’s getting to look like a zombie. Is she well?
2. n. a very stupid person. Please ask one of those zombies to stand by the door.
3. n. a very tired person. I feel like such a zombie. Maybe I’m not eating right.
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • zombie
  • come to life
  • come alive
  • zombie out
  • back from the dead
  • come back from the dead
  • bumble
  • bumble along
  • bumble through
  • literally