A malinformer whose effect is socially disruptive. The most familiar species on Everything2 are probably mallinkers and false nodevertisers. Some performance art involving news hoaxes is also clearly the work of infopaths. Moving up the scale, we have the creator of the original Word macro virus ("this is enough to prove my point") (but not his successors). At the radical horrible extreme we find cult leaders.
Infopathology is not the study of infopaths.