The Hitch Hikers Guide to the Galaxy/Babel fish

Highly improbable biological universal translator, in The Hitch Hikers Guide To The Galaxy by Douglas Adams. In the novels, the Babel fish was a small fish which, when inserted into the ear translated all languages for the user. This was both a useful plot device for Adams, and the starting point for a joke about the existence of God.

The name refers to the Tower of Babel which is a building refered to the Bible. And of course to fish. The story is supposed to describe the events which lead God to introducing different languages into the world.

This inspired the name of an on-line translation service: http://babelfish.altavista.com