Murray and Thomson became friendly over the course of filming. At one point they engaged in a series of dangerous one-upmanship contests.
It quickly escalated and after many drinks and after much arguing over who could out-Houdini whom, Thompson tied Murray to a chair and threw him into the swimming pool.
Murray nearly drowned before Thompson pulled him out.
Thomson was brought to the set for consulting, but he said he only really walked around and fired guns.
One thing he was good for, though, was showing Bill Murray how to be him, leading by example. Within two weeks of Thomson being on set, Murray had transformed into him.
So much so that when Murray appeared on ‘Saturday Night Live’ starting its fifth season, he was still in character, complete with long black cigarette holder, dark glasses, and nasty habits.
'Billy,' said one of the writers, echoing several others, 'was not Bill Murray, he was Hunter Thompson. You couldn't talk to him without talking to Hunter Thompson.'"
