Started by the Cocky Diddy kong mainer "Japan" on the Awesome Allisbrawl.com site started by the owner "nealdt", the term "P.U.G" has a variety of meanings on the interwebz mainly in the Smasher bros. community:
P.U.G is a term used in the Smash bros community, usually to describes a n00by bragger or a person who goes around bragging stating that he or she rapes pro player's Alt. Characters on Wifi mostly in 1v1s or FFA's and or Coin matches with Items on high, in a game universally knowned as "Super Smasher bros. Brawl"
Person 1: LOLOLOLOL!!!1!!
Person 2: Dude, what is it?
Person 3: yeah dude, what?
Person 1: I totally just 2 stocked and beat Samboner's Yoshi in a FFA today!! ROFLOLOLOLOLOL!!
Person 2: and? o_O?
Person 3: Sam dosn't use Yoshi at all n00b -__-
Person 1: so what? I still beat him! :D
Person 2 & 3: Samboner sandbagged you ROFL! XD, your a P.U.G! :P, No johnz get rape
Person 1: T_T