The "Other" category is anything greater than the highest category. I may add more categories if I write things beyond these word count categories.
This year, my longest blog post at BS Detector by word count was ~3500 words. I also wrote an article that was ~5500 words, but it had a large interview component which I don't think would have qualified as strictly "my" writing. I also think I may have written some pieces of fiction that stretched over 5000 words, but they're unfinished or in some partially complete state.
This question will be determined by the longest thing I write that is started and completed within 2026. It doesn't have to actually be published, although I suppose I'll be able to provide proof that I wrote it through sharing a screenshot of the word count of the google doc or some such thing.
I probably won't bet that much in this market, and likely would only bet as motivation to finish something.