WATCH: Man with baseball bat bashes bicyclist while onlookers watch in Brooklyn

Shocking video posted on  Thursday shows footage of a man getting repeatedly hit by a man with a baseball bat in Brooklyn. People pass by and do nothing.

"Brooklyn: Flatbush Avenue & Parkside Avenue, person #CaughtOnCamera beating up a biker with a bat until he falls to the ground unconscious."

The incident happened at around 5:30 in the afternoon on Wednesday.

One can see in the course of the video the 54-year-old man on a bicycle beaten to the ground, as he is hit six times with a baseball bat. At one point he raises his arm in a futile attempt to defend himself.

Finally, a man runs up and tries to talk the aggressor down, who hits the man with the bat twice more while the two are talking.

The attacker leaves and comes back to the scene and returns twice, yelling and screaming at the victim, who is now in critical condition in Kings County Hospital and hasn't regained consciousness as of this writing.

The man with the bat was arrested at the scene and has been identified as 46-year-old Ashanti Robinson. He is now facing charges of weapons possession as well as menacing and assault in connection with the brutal attack.

There is no information available yet as to how the incident started.