Police shared video of the suspect blocking a Waymo car and shouting at it before the attack.
It happened July 5 around 1 a.m. near Buchanan St. and Washington St.
Police say the victim, who was outside of the Waymo, told the suspect to let the car leave.
That's when the suspect lunged at him and then assaulted him.
Officers say he was found unconscious and had life-threatening injuries, including a fractured skull.
The victim's family says he is cognitively impaired and visibly disabled.
If you have any information about this incident, you're asked to contact SFPD.