One of the several emoticons used to express exasperation and/or mild panic. (The semicolons symbolize beads of sweat on the long face of the person using the emoticon.)
Someone Stupid (not me): Aaaaaah!!!
Sam: What did you do now...
Someone Stupid: I spelled history shitory on the big history essay we just turned in. TT.TT
Someone Else (not me): Aaaaaah!!!
Sam: Now what...
Someone Else: A rabid gorilla is chasing me 'cause I have a banana in my butt pocket!
Sam: -_-;;; We better start running then...