This article is from the Viruses and the Mac FAQ, by David Harley D.Harley@icrf.icnet.uk with numerous contributions by others.
This probably doesn't belong here. It's a PC file infector which
works with a number of PC executable file formats. When it was
first seen, it was reported to be a multiplatform virus capable of
executing under some circumstances on Macintoshes. Subsequent
reports indicate that this belief results from misinformation on
the part of the author. However, at least two reputable PC
anti-virus vendors still list it as capable of activating on a
Macintosh. No Mac scanner is known to attempt to detect it.