It's also because of how Maggyo (Stunfisk) hit the Pokemon fanbase as a complete troll Pokemon. If you look at its animation in-game (and its behavior in the anime), it's obviously a goofy one, which makes it quite amusing to think of. It has been rechristened "Derpfish" by many fans. All-in-all, it's basically kin to Slowpoke, Bidoof, and the like. As mentioned by Nica, to "Stunfisk" is another way to say that the forum has suffered a Database Error (DBE). Maggyo was chosen to herald the DBE page because of its derpish look, as well as its typing as an Electric-type possibly causing electrical problems on the server if it ever actually "landed on the site".