There seems to be a virus going around on the mailing lists at Google (at least, possibly elsewhere too), and I was the lucky recipient of such a mail. When Thunderbird tried to download the virussed-up "package", Officescan stepped in and presented me with the following informative message:

"Oh no! OfficeScan has detected one or more virus/malware on your computer...
For detailed information about the virus/malware, click the virus/malware name.

There is something on your shirt."

... Wait, what?!