Late in the film, we discover that Cliff purchased a cigarette dipped in acid from a hippie. He stores the item on his person for a time and then decides to light 'er up and turn in for the night. As the sensation finally kicks in, the Manson murderers, led by Tex, burst into the house and threaten Cliff's life.
Now, the fact that he's tripping on acid could explain why Cliff is so nonchalantly violent towards the invaders and utterly unsympathetic to the deceased once the chaos subsides. The drug seemingly affects his mind in a manner that dulls his senses, so much so that he doesn't even notice when one of the attackers stabs his leg with a knife.
Still, this particular character beat doesn't lend much to the story and feels more intrusive than necessary. We follow Cliff around Rick's house as he slowly deteriorates into a cloud of giggles and paranoia, mannerisms that run contrary to the rigid, extremely in-control demeanor the stuntman displayed in the previous two hours. Why did Cliff have to take acid? Was it essential to the story in any way, shape, or form, or merely a baseless gag designed to provide levity to the dark finale?
At any rate, this feels like Tarantino excess — a beat that certainly induces laughs, but could just as easily be excised from the picture without losing much of anything.
