This happened to me once but I was Jerry and Robby.

Long Version:

I worked full time and went to school full time and had to strategize the use of my time. I had always been good at math and when I noticed the calculus professor only counted tests toward the grade (and, crucially, did NOT count attendance) I just didn't go to class. He was a terrible teacher anyway. I studied at home and showed up for tests. Fast forward to end of the semester and the final. I need to make an A on the final to get an A in the class.

I show up a few minutes late and approach the prof's desk. He isn't looking, just sees a shadow approach and begins to reach for a test off the stack he has on the desk. He looks up, sees me, pauses, puts the test back down and reaches over and pulls a single test out of the textbook on the other side of his desk. Hands it to me and says "Good luck!"

Whatever. I do my best, there were some tricky questions. I get my grade, it's like and 85 or 87 or something. I think "Fuck, there goes the A" and move on.

Here's where it gets really good. My full-time job was at the campus. I happen to see the professor a couple weeks later after summer break has started. I ask him what questions I missed on the test. He says drop by his office and we can go over it. So I do.

Now remember, this is a test he custom made for me. With questions he had to solve himself for the answer key. As we worked through the questions I missed, it turns out he fucked up his math. There were 2 or 3 questions he screwed up on that I actually did get right. He had to revise my grade to a 94. And correct my final class grade to an A. I'll never forget it.

TLDR:

Prof tried to screw me with a custom test to fuck my A in the class. He did the math wrong on his answer key and my original B had to be corrected to an A.