Stun guns and tasers are less-than-lethal tools for controlling violent suspects. They serve to demobilize the target and cause serious, but not excruciating, pain. When a police officer uses a stun gun or taser on a suspect, they can usually count on that suspect going and staying limp. Because of this, it’s an extremely stupid thing to use as a cattle-prod: victims lose the physical capacity to comply with orders, because they’ve been paralyzed!
With that in mind, take a look at this incident, recorded by camera phone in Powell Library at UCLA: youtube link. Mr. Tabatabainejad allegedly went limp while being escorted from the library by police officers, who were removing him because he was not carrying his student ID. He was verbally combative, as is customary when bureaucratic requirements are being violently enforced, but the result is, to my eye, quite clearly excessive force. As many of my readers know, I have worked as a civilian investigator of police misconduct, so I will claim some authority on this matter. Frankly, though, the video testifies with greater authority than I could ever muster.
Here is a link to a Lancet study: “Effects of stun guns and tasers.” It establishes the demobilization effects that tinged this incident with such sadistic ignorance.