Aaron Hanna, 30, pleaded no contest to the charge on the condition of no state prison time and up to one year in jail, Wagstaffe said. His attorney said Hanna would be entering the Delancey Street treatment program in San Francisco upon his release.
Hanna was arrested March 2 after he and his acquaintance were traveling together after having shared a meal, prosecutors said.
The two stopped at a Chevron gas station in San Mateo and the victim was checking under the hood of the car when Hanna came up behind him and struck him with the cylinder that he found on the ground nearby. Police originally reported that the weapon used was a sledge hammer.
The victim was able to avoid the brunt of the blow and received just a glancing blow to his neck, Wagstaffe said. Hanna then jumped into the victim’s vehicle and fled the scene.
Hanna was arrested a short time later on Skyline Boulevard in San Bruno, Wagstaffe said, and the victim’s vehicle was recovered.
Hanna is scheduled to return to court Oct. 8, Wagstaffe said. He remains in custody on $150,000 bail.