Tony Rocky Horror

Think about it this way: what do you think Marsellus is going to say about calling off the hunt for Butch? He definitely isn't going to say "I was getting raped in my asshole by two rednecks and Butch saved me, so he's off the hook." He probably won't give anyone a reason at all. So what rumors will be going around? They'll likely know Butch surprised Vince in his apartment and killed him, making it even more mystifying that Butch is no longer targeted. "They" will make up all sorts of stories about Butch overpowering Marsellus, or blackmailing him, or conspiring with Marsellus to kill Vince for fucking Mia on their date together, or who knows what? This suggests to me that the story going around about Tony Rocky Horror is likely a complete fabrication, as Marsellus would have shared his reasons with no one, leaving his subordinates to guess and spread rumors.

And the more I think about it, the more I think that would be the rumor-- Vince slept with Mia, and Marsellus set him up by sending him to Butch's apartment, then telling Butch if he kills Vince and skips town, he's off the hook.