A young man is stabbed in broad daylight and falls to the ground, blood pouring from his wound. People recoil in horror. It sure looks convincing, until you see more.

The same guy is stabbed again. Then, Josh Lin is stabbed a third time. The stabbings are fake. The knife has a blade that retracts into the handle. The blood is fake, too.

Josh Lin told INSIDE EDITION's Jim Moret he was doing a "social experiment" to see how people would react to an act of violence on the streets, including Hollywood Blvd., one of America's biggest tourist attractions.

Moret asked, "Do you understand why somebody watching this video would be angry with you?"

"Yes, especially the ones that tried to help," answered Lin.

Sometimes the stunt backfires.

In one incident, a Good Samaritan actually tackles the "stabber," then freaks out when he realizes he's been deceived.

Cops are blasting the videos.

One resident said, "That's going way too far."

Another resident told INSIDE EDITION, "I think this person should go to jail."

One video viewer remarked, "All of the people involved in this 'prank' are absolute morons."