These are dangerous memory resident parasitic viruses. They hook INT 21h and write themselves to the end of COM files that are executed. They contain errors and sometimes infect the files incorrectly.
"Mutator.307" does not check neither the file format nor file name extension and infect EXE files as COM files, as a result these files halts being executed. This virus contains the text string:
Mutator v2.0b
"Mutator.459" contains the text:
MUTAtOR (C) Mutation Inc.
"Mutator.780" is the encrypted virus. Under tracing it displays the message:
Fuck you, asshole!!! You're using a Debugger!!!
On October, 30th it displays:
Hey! Holloween almost here!
Better be good, or the demon's will get you!
It also contains the text:
[Mutator] C/B: MainFrame [Mutation INc.]
