So, for those of you who have played through Blackrock Mountain, you might remember, that in the fight with High Justice Grimstone, he has an intro line for each card in his deck. The idea is that, we come up with lines for legendaries that have come out since.
So, for example, King Toggwaggle: "He's got eyes for treasure as bright as his candle, please welcome, King Toggwaggle!"
Edit: As an addition, you can suggest a legendary for the next person to do. Or not. Your choice.