Shoulda checked it in the first place:

    GET https://muffinman.io/js/posts/glitch/parser.js [HTTP/1.1 200 OK 138ms]

    Uncaught TypeError: animation is undefined
        parse https://muffinman.io/js/posts/glitch/parser.js:263
        Monorail https://muffinman.io/js/posts/glitch/monorail.js:327
        <anonymous> https://muffinman.io/js/posts/glitch/index.js:10
        <anonymous> https://muffinman.io/js/posts/glitch/index.js:5

FF 138.0.1 (May 1, 2025)