Gang stalking is where various people with the same agenda attack you in some way.
The techniques may include sabotaging your work at work, spreading false rumors, bullying, and trying to convince your employer to fire you.
Usually these are full-time bullies who get a thrill from trying to destroy a persons life.
Rather than seek help for their psychopathic behaviour, they'd rather form groups (a gourp of people is stronger than an individual, and has many advantages), and attack people for arbitrary reasons.
An example of gang stalking is where one, the gang stalking rat, picks out a target, usually somebody he has a grudge with, then attacks them. Then he or she calls a friend who they know will help them. That person attacks the victim, then calls somebody else whom they know will join in, and the pattern continues.
There is power to be gained from Gang Stalking.