Argh! Where Was It?

[LilFluff]

Lost track of a one-shot story that I thought I'd been linked to from here. It's a fairly short one-shot with Batman and a shell shocked Pinkie Pie who depending on how one looks at it either didn't handle meeting the Joker well or dealt with it in a properly final manner (she just couldn't accept the way he was tainting laughter). Rather a clash of setting tones, but I thought it was done well.
-----

Will the transhumanist future have catgirls? Does Japan still exist? Well, there is your answer.