Tug Bug

You almost suspected it: The Tug Bug is a device from a computer game which Alex Fredebeul and Peter Kienle set out to create in the late 80s.

Because Peter relocated to the US in 1988 the game never got finished but the Tug Bug is popping up every once in a while. Here's the earliest incarnation:

Recently the Tug Bug has been seen together with Marvin, the Robot lugging acme records CDs around.

Rumors have it that the original source code of the game has been found and is now being implemented for the Macintosh.