A fat/ugly girl who appears "attractive" over a social media site's pictures; i.e. Instagram, facebook, myspace, etc, and is ugly or doesn't look anything like the picture in real person.
Ian: Samira looked HOT on her profile picture on Facebook, but when I met her yesterday, she was a fat goomba dude!
Jesse: You gotta watch out for those goombas man! They're everywhere playing tricks on us n' shit.