Mystery meat navigation (also known as MMN) is a form of web navigation user interface whereby the target of each link is not visible until the user points their cursor at it. Such interfaces lack a user-centered design, emphasizing aesthetic appearance, white space, and the concealment of information over practicality and functionality. The term was coined in 1998 by Vincent Flanders, author of the book and accompanying website Web Pages That Suck.
The epithet "mystery meat" refers to the meat products often served in American public school cafeterias whose forms have been so thoroughly reprocessed that their exact types can no longer be identified by their appearances; similarly, the destinations of links using mystery meat navigation are unknown by appearance alone. Using such a navigation has been likened to processed meat products as "you're not sure what meat you've got until you bite into it". Flanders originally and temporarily described the phenomenon as Saturnic navigation in reference to the Saturn Corporation, whose company website epitomized this phenomenon.
The practice of mystery meat navigation may be defined as "frivolously concealing navigation options through rollovers and other tricks. It is considered problematic on information-rich websites because it makes it difficult for users to recognise the destinations of navigational hyperlinks, or to discern where they are, and this increases the time a user takes to learn to use the site.