In the movie, the villains (humans) had waldoes—which are a classic sci-fi invention, as are the movie's "avatars", but that's a separate discussion—as seen in Cameron's magnum opus Aliens.
In Avatar, the waldoes are entirely military. As someone said, "It's Fern Gully meets Halo." (The Boy objects to that, and since I haven't played Halo, I don't know. The Fern Gully part is dead on.)
Anyway, the waldoes are loaded up with guns and missiles and, in the climactic battle, a knife.
I'm not kidding. The giant robot had a knife. A big Crocodile Dundee-style "that's not a knife" knife.