Not the show you describe
Ronald McDonald is a trademark, and his appearance is copyright owned by the McDonalds corporation. That means that subject to an exemption, only McDonalds can decide what happens with Ronald McDonald.
As described, you are going to use Ronald McDonald, not a generic clown that evokes Ronald McDonald in a comedy/horror. The most relevant exception that springs to mind is the trademark Parody exemption (and a similar exemption that exists for copyright fair use).
Your movie doesn't appear to be a parody - the idea of a murderous clown protecting a burger chain is not, on its face, a parody of McDonalds. That is, it might be funny (or not) on its own terms, but it is not obviously poking fun at McDonalds which is the essence of parody. Obviously, your plot outline is brief and perhaps the full script is an incisive commentary on the way McDonalds is doing ... something.
Further, famous marks have extra protection - works that tarnish the mark are more likely to be considered infringing. Tarnishment happens when a distinctive mark is depicted in a context of sexual activity, obscenity or illegal activity. You know, like a crazy lunatic murderer.
Compare and contrast with this parody:
This evokes McDonalds but it doesn't use any of their trademarks or copyrighted material and it also evokes other fast-food restaurants. The parody elements are clear: it clearly isn't McDonalds; it only uses as much material as necessary to get the audience to make the link; the joke is about fast-food restaurants: their sameness, teen-worker-exploitation, promotions, crap food etc.
When they do explicitly compare Krusty Burger with McDonalds the joke is about McDonalds:
Lou: Y'know, I went to the McDonald's in, uh, Shelbyville on Friday night.
Chief Wiggum: The McWhat?
Lou: Uh, the McDonald's restaurant. I never heard of it either, but they have over 2,000 locations in this state alone.
Eddie: Hmm. Must have sprung up overnight.
Lou: You know the funniest thing though? It's the little differences.
Chief Wiggum: Example.
Lou: Well, at McDonald's you can buy a Krusty Burger with cheese, right? But they don't call it a Krusty Burger with cheese.
Chief Wiggum: Get out… well what do they call it?
Lou: A Quarter Pounder with cheese.
Chief Wiggum: A Quarter Pounder with cheese? Well I can picture the cheese, but… uh. Do they have Krusty Partially Gelatinated Non-Dairy Gum Based Beverages?
Lou: Mmm hmm, they call 'em Shakes.
Eddie: Huh, shakes. You don't know what you're gettin'.
