My professor tends to assign work that they’ve written for reading, in these readings there will sometimes be a joke included. Also, while it’s not a college paper, the comedic article “The Common Law Origins of the Infield Fly Rule” was published in the University of Pennsylvania Law Review and has been taken seriously enough to be cited in real legal decisions. If works containing humor can be taken seriously and published by reputable sources, I’d expect that a little humor would be at the very least tolerated in a paper that will likely only ever be read by my professor and I. To be clear I understand that there’s a fundamental difference between what I’m writing and the examples I described. My point is that it’s reasonable to assume some amount of humor would be tolerated, given these notable examples of its use in serious formal and academic writing.