O97M.StrangeDays is the first known Office 97 virus which can migrate between Word and Excel environments.

The virus is able to travel between the two environments because Word and Excel share the same macro language core, Visual Basic for Applications 5, in Office 97. StrangeDays contains no Word or Excel specific code and is therefore a true Office 97 virus, able to cross-infect the two. The virus even includes code which attempts to automate such cross-infection. Fortunately, this code contains bugs and does not work correctly.