Urbandouches are people who try to add a definition on Urbandictonary or randomly enter chat rooms and spew hate about one specific person.
Joe: hows life?
Bob: good
"Sed has enterd the chat room"
Joe: hi...
Sed: OmG jEnNIfEr IS a TOTally BItCH!!!!! shES fAt aND HaS no FRIENds!!!!!
Bob: who are you?
"Sed has left the chat room"
Joe: what an URBANDOUCHE
