>>108958706
You just want a mascot without anything else? You can even do it with a ublock origin filter like so:
4chan.org#$##custom-mascot-container:has(~ #bottom) { display: unset !important; }
4chan.org#$##custom-mascot-container > img {z-index: 1; position: fixed; bottom: 0; right: 10px; width: 15vw;}
! the display: none in the html, and unsetting it in the css is so that it doesn't appear massive on the initial paint before the css has been rendered :)
4chan.org##+js(trusted-create-html, body, '<div id="custom-mascot-container" style="display: none;"><img src="DATA URI WITH BASE64 GOES HERE"></div>')
You can convert your image to a data uri with https://base64.guru/converter/encode/image (select it in the output dropdown), and copy paste it.
Probably better to do it in a userscript but I can't be bothered lol