[NSFW] Anime OP for 2ch Guro Board Mascot "Cut-in-Half-Girl"

I am looking for a web animation. It was made by someone on 2ch of one of the Guro board mascots, and made in the style of an anime opening. I get the feeling this girl's name was "cut-in-half-chan" or something silly.

The character was an anime girl that was, well, cut in half vertically down the center. She was alive and well, going about her day in this animation, hopping on one leg to school.

I made illustrations of the girl and some scenes I remember from this animation. The details may be off, but these are my general memories:

(there was another mascot, this one cut in half the other way)

At one point a gashadokuro raises up from the ground.

The red sky is split in half by a plane flying overhead.

This was from the early 2000s, before youtube or NicoNico IIRC. It was probably made in flash, and was hosted on another site. I believe someone from the Anime and Manga board on GameFAQs must have linked to it.

I've been looking for this particular animation for over a decade, I'm not sure it exists anymore, and I haven't found any references to it either. Making the search harder is the fact that the media was in Japanese, and only on Japanese sites.

I am also NOT a fan of guro/gore so the search has been...rough. And I don't encourage anyone to try searching for this if you don't want to see any horrible things.