(Portland, OR)  --  A man is facing charges after a crash in which he landed on top of another vehicle and then allegedly pointed a gun at witnesses.  The Portland Police Bureau says 22-year-old Shabar Johnson crashed into a car inside a parking lot off Southeast Foster Road in southeast Portland yesterday morning, partially landing his vehicle on top of the car's hood.  No one was in the parked car at the time of the crash.  Police say Johnson then got out and was trying to pull his car free when some passers-by confronted him, prompting him to allegedly pull out a gun and point it at them.  He then fled on foot.  Responding officers found him near Southeast 96th and Harold Street and arrested him on charges of menacing and unlawful possession of a gun.