Every year since season two of The Simpsons, in 1990, the series has done a Halloween special, which is not part of the show's normal continuity. These special episodes may air anytime from the first week of October through the first week of November, so it's important to check the schedule at least a month in advance, if you want to be sure to see it. (I mean, in case you don't already watch every episode of the regular series.) Anyway, the Treehouse episodes will have at least three segments, maybe an extra one before the opening credits, and of course the opening credits themselves will be specially modified for Halloween. Same with the closing credits. And usually, if not always, at least one of the segments will include aliens called Kang and Kodos, either in a major role or a small cameo. Um... I suppose I couldn't possibly have seen the thing when it first started, because I didn't have FOX at the time. I may have seen some of the older Treehouse episodes in reruns, years later. Or not, I forget. And I don't remember which episode was the first one I ever saw first-run. But at some point I decided it should be a tradition to always make sure I watch each new Treehouse episode every year (even in years where it might be the only Simpsons episode I watch that season).
I started this page sometime after Halloween in 2013, thinking that someday it would be nice to rewatch every episode and write a review here. But every year since 2003, I had written at least a little bit about each year's episode in my Halloween journals. And in 2014, I decided I might as well copy and paste those descriptions to this page. I'd still like to watch the eps from before 2003, and until I do, I won't be listing them here. But even the ones I do list here, I should also rewatch, because for many of them, I barely said anything about them other than whether I liked them or not (though for some I said a bit more). Of course, my describing the plots isn't really necessary; that's what the links are for, after all. (But I made my first full entry here in 2014, while watching that year's episode. Which I should do every year from now on, hopefully.)