No intentional damage. CDEF - infects desktop files. No intentional damage, and doesn't spread under system 7.x. Code 1 - file infector.
Accidental system crashes possible.
Code 252 - infects application and system files. Triggers when run between June 6th and December 31st. Despite the message, no intentional damage is done, though shutting down the Mac instead of clicking to continue could cause damage. Can crash System 7 or damage files, but doesn't spread beyond the System file. Doesn't spread under System 6 with MultiFinder beyond System and MultiFinder.