A non sequitur interjection meant to imply ADD (attention deficit disorder). So called because it seems the stereotypical thing a young girl might scream when having her attention distracted by ponies. Common in many online forums.
Wow, I just read in the Washington Post about a secret US plan to attack China. Now this would obviously be a terrible--OMG! Ponies!!!
av SkidMarkyMark 1 juni 2006