Thanks to Digitalboy for the heads-up on this one, from the 97th episode of Gintama. Honestly, I’d be surprised if it was the first occurrence of such a thing in the show given the general parodical silliness that permeates it, but I’m not really inclined to go back and watch all the prior episodes to find out – I don’t watch anime Gintama. I did read the manga through to about volume… seven or eight, I think. I’m not entirely sure why I stopped reading it, come to think of it – I do enjoy it, and I’ve probably got a stack of unread later volumes lying around too. I should probably get back to it…