What do the red ampersands above my character's head mean?

I'm on Playthrough 2, at Level 50, playing Zero the assassin. Recently I was doing a quest in Eridium Blight and when I went to jump into my vehicle, I noticed that there were two red ampersands "&&" above Zero's head as he crawled over the hood to get in.

I know that NPCs will have a green exclamation point above their head when you're ready to turn in a mission, but I don't recall ever seeing these red symbols before, and wasn't sure what they mean. They were gone the next time I exited the vehicle.

Game glitch or actual real indicator of something?

Edit: It just happened again, this time it was one red question mark. I enabled the quest Monster Mash Part 2 and left Eridium Blight via the exit to The Dust. After the new map loaded, I exited the vehicle to check my inventory, and when I went to get back in, Zero crawled over the hood and had a red question mark over his head.

Solution 1:

It's part of his character animations. They are random, much like the random voices each character has when you open a menu. I can't recall the full list, but I do remember the !, &&, and :D as icons that have shown up.

Here is a full list of emoticons that show up.