Gelatinous cube

A gelatinous cube is a fictional monster originally created for the Dungeons & Dragons role-playing game. It is a ten-foot cube of mindless, gelatinous matter that slides from one place to another, absorbing everything in its path. Because of its obviously fantastic, non-realistic nature, the gelatinous cube is one of the most well-known monsters created especially for role-playing games. Although it is based upon famous fictional monsters (especially the movie The Blob), it exists primarily as a role-playing game monster, and not a monster taken from outside sources (such as many mythological monsters including the minotaur or troll) and adapted to a role-playing setting.

Despite its popularity (or perhaps because of it), the gelatinous cube is also widely known as one of the sillier role-playing monsters.