SHADY FRIEND SHOWS UP AT HOSPITAL . . . DEMANDS ACCESS

Lamar Odom had a visitor Monday night . . . a guy who claimed to be Lamar' s assistant , insisting Lamar had summoned him . . . but hospital officials smelled a rat. the guy arrived around 11 PM and got on Lamar ' s floor when security stopped him. He said Lamar had called him and he came down from Vegas because Odom was insistent on seeing him. the guy has a history with Lamar and Odom' s people believe he facilitated Lamar' s drug use . The 2 men lived together in Vegas at some point . We ' re told Lamar ' s management fired the guy the day Lamar went into the hospital . Security was unbending and refused to let the man in . There was yelling and "a big scene " before he was escorted out . Khloe was not at the hospital when it went down .