GB2AC is short for Go Back To Avatar Chat. This is commonly used on the Battledome Chat board on Neopets as an insult. This is generally only used when a troll or mindless attention seeker comes to ask stupid questions on the BDC (Battledome Chat.) Avatar Chatters hate it when people from the BDC say this to them and take offence and sometimes bring a hoard of their avatar chatter buddies to attack and flame the BDC. Most of the time the BDC people will find this humerus and egg on the hoard of angry avatar chatters by saying things such as "umadbro?" This often ends in multiple frozen accounts and or warnings/suspensions.
Avatar Chatter makes a thread something like "You are all rich right!?!?! So give me free stuffs yeah!?!?" and might look something a little like this:
ACer: WHY NOT?!? You don't need it, it's fake, so GIVE ME IT!
ACer: EXCUSE MEH!? STUPID BDC NOOB
*ACer brings a mini hoard of drones to help fight with them*
ACer: STUPID NOOBS THINK YOURE SO GOOD AND *dung*!!
ACer2: YEAH YoU aLL faiL At LiFE! NoObs!
ACer3: BULLIES THINK YOU ARE SO MUCH BETTER THAN US!?
ACer2: SHUT UP!!
ACer: NOOB! I'm NOT mad just like using caps lock OK!?
BDer: Yea umadbro
ACer: Fu!# YOU G@YBO RAWWR!
ACer3: YOU ARE AN IDIOT W@#%ER!
BDer2: Lol n00bs =) *Sprays noob be gone*
ACer2: F### YoU GIRL! LOsEr!
TNT: *Ice ice ice ice*