I don't know where to begin with this—literally, figuratively, existentially? It's a new browser ARG thing by Nathalie Lawhead who has made many odd things wot RPS folk have enjoyed like Froggy and Cyberpet Graveyard. Mackerelmediafish.com, which I suppose is the website and also the name of the game(?), is another such clever oddity.
Welcome to the internet of yore where gifs have three frames apiece, your CRT monitor flickers, and everything your mouse hovers over has some wild effect. Also there are actual mice, gif mice, inside the website feasting on the dead links which you must explore and then feed them. There is a fish who has lost their friend somewhere in a very bad demo game.
Finding the fish's friend and feeding the mouse named Verm will net me the keys to escape the fishy site. Except then it appears I are trapped somewhere new. I've found an ancient place, beholden to the old ways before the internet changed.
The entire experience is a portal back to my childhood when the internet was, if not weirder than now, differently weird. I haven't found one yet, but I'm fully expecting to find something that resembles an edgy instant messenger away message. There's a PDF full of MS Paint drawings alongside the lyrics to what I'm almost certain are a Gwen Stefani song. Ah wait, the PDF is a tiny zine, likely made with the Electric Zine Maker, another of Lawhead's projects, mentioned on the previous page.
It's probably best if I stop telling you about the thing now so you can just try it yourself if you like this sort of thing. Go then, try to escape the fish website.