So i was doing my daily quest in bash'ir's landing, the mana cell one, and i used the phasing object. then i saw a shaman hordie, decided to gank him, then i had a warlock dot me up, and then he left the phased mode, my pet however continued to attack him while in phase, making him invincible and invisible to the warlock, while it was still able to beat him down!
just so happened that the warlock was a roommate of someone on the alliance side, i got a whisper a minute later confirming it lol.