You can have one keystroke send your user identification, another for your password, and a third key to send a sequence of commands.
"The Online World"
Odd de Presno
Perhaps an unusual keystroke by an unwitting computer user on those systems which seemed only mildly affected could trigger something in the worm.
"Underground"
Suelette Dreyfus
One keystroke might begin an irreversible chain of commands to erase everything on that system.
"Underground"
Suelette Dreyfus