Well, for MoP that would be Iron Juggernaut done with 20 Affliction Warlocks and all of them using 4 trinkets. You could then watch the boss die well within the first phase 1 and a couple of those locks (the ones that actually had all four trinkets and the meta gem up simultaniously) ending up well beyond the 1m dps mark. That's just silly.
You could then just go on, pick up Chi-Ji's buff on the timeless isle and curbstomp a celestial with your warlock-raid.