1. Be a rogue with glyph of disguise.
2. Find a low level on a quest which requires him to kill humanoids.
3. Turn off any in game titles on your character, take off your weapons, and pick pocket the mob so you look like it.
4. Turn on walk, and start behaving like a mob (only walk in a straight line, no keyboardturning, change direction after stopping).
5. Oh, and turn on PvP.
6. Lowbie probably attacks you as he thinks you are a quest mob :P