Hidden easter egg - famous story, I already heard it before but could not remember which version it was for v1.2 or v1.3. I read about it years and years ago or so on a web page that no longer exists. Much of those old stories no longer exist on the internets (most now are just rehashes and copies of existing webpages).
If you read ars technica and commodore: on the edge as well as amigahistory.co.uk you will get an excellent overview of the history. Unfortunately it's only 3 sources (i.e. they themselves may contain mistakes). Old archived newsgroup messages also contain some gems.