User blog comment:ANYStickman/Death Of A Character In Season 26/@comment-50.172.98.140-20141005232923

Guys. Seriously, this has been answered a long time ago. Just LOOK IT UP. Anyway, here it is:

http://www.tv.com/shows/the-simpsons/community/post/the-simpsons-who-died-clown-in-the-dumps-krusty-dad-rabbi-krustofsky-141200807586/

Anyway, yep, it was Krusty's father, Rabbi Hyman Krustofsky, which explains the title of the episode; I mean, Krusty would naturally be pretty torn up about that, right?

So, I guess that pretty much clears that up...