I remember when MoP patch came out during cata when Shockadins were big. I just basically walked in Ironforge and took on 3-5 allies at a time and killed each one while keeping myself up.
or was that cata patch during WotLK. It has been so long. Point is, I havent seen anyone take on 5 people like that other than that time.
If you were talking about in a season, then definitely that Resto druid TBC, although, my Assassin rogue would kill them every so often, back when Mutilate was required to be behind the target. That burst with poisons hurt their dots just enough to make them die for me. Could not do it as sub.