The grupfish is extremely unusual among fish in that it isn't one. Not only isn't it a fish, it isn't actually an animal at all. As a matter of fact, it isn't even a noun - it is an adjective.
Grupfish is a word that originated in the Xurient, and is used to describe things that look surprisingly unlike what you would have assumed just from hearing about them. For instance, Xuriental houses are often decorated with what are referred to as scales, which turn out to be very long, conical and fuzzy when you see them instead of the short, flat, overlapping round plates you'd expect. Other examples of things that are Grupfish are Tuckagotchas, which are called Virtual Pets but do not in fact look anything like real pets, and yesticale worms, which don't look anything like yesticales.
According to Xuriental legend, there once was an actual creature called the "Grup Fish", which was punished by Lumawig, the great spirit, for being a bird instead of a fish. Lumawig changed the beast into a word. This was not the word Grupfish, as you might expect, but was in fact the word Hungfold, which has a completely different meaning.
It is worth noting that there are people who believe that Grup Fish really did - and still do - exist, although these same people are often the sort who try and do silly things like farm Fish-Trees, which as everyone knows is a futile exercise even if it were possible to keep them from escaping. Come to think of it, the Fish-Tree is another wonderful example of something that is Grupfish.
--Dfaran L'Eniarc 01:24, 30 Jun 2005 (EDT)
Why the splak would you expect yesticale worms to look like yesticales? Do you likewise expect horse-apples (speaking of splak) to look like horses? --John Cowan 13:00, 14 Aug 2005 (EDT)
You'd expect yesticale worms to look like yesticales if you heard their name, which is "Yesticale Worms", since it contains the word "Yesticale", which is exactly the same as the word that is used to refer to yesticales, namely, "Yesticales". Sheesh, I would have thought that was obvious. Besides, horse-apples DO look like horses. --Dfaran L'Eniarc 00:56, 2 Oct 2005 (EDT)