Take Shadow Labyrinths, for example. The first boss, Ambassador Hellmaw, gets upgraded to a level 72 monster with a room-wide AE fear and Chromaggus' poison breath. At 67, you'd better have a bank full of +hit gear, if you want on this ride.
It was a painstakingly long fight, but we finally whittled him down and killed him. In a solid level 70 group, he would probably be a joke, but at 67 he's a challenge. Upgrading a tier 2 helm makes it worth the trouble though:
The Badge of Justice is a token used to purchase any of these items.
The second boss was a completely different story.
That's Blackheart the Inciter. Anyone want to take a guess why he's just standing there watching us, laughing? I guess I'd laugh too, if I were able to mind control five people at once and have them kill each other while I watched.