Haunted mementos are so cool. They're untargetable ghosts that follow you around (except they go really slow and can sometimes get lost). You also get a buff/debuff called "Haunted: something is following you". I got mine in the Eastern Plaguelands as a drop when the scourge were attacking a while ago. I assume they won't have that event again, because I think it was just a special event for the WOTLK launch. Anyway, if you want one you can try to find one in AH since they don't become soulbound.
