noooooooo
Explanation
The Joke
A woman excitedly tells a man: "Hahahaha! You know your theorem on homeomorphic function construction? I found a way to use it to cure cancer!" The man screams: "NOOOOOOOO!!" The caption reads: "Funtime Activity: Forcibly converting pure mathematicians into applied mathematicians."
The Humor
The comic plays on the well-known cultural divide between pure and applied mathematics. Pure mathematicians pride themselves on working with abstract concepts for their own sake, with no concern for practical applications. Finding that their work has a real-world use -- especially something as important as curing cancer -- would be horrifying to a pure mathematician, because it retroactively transforms their beautiful abstract work into mere "applied" math. The joke is that being told your theorem can cure cancer, which anyone else would consider the greatest news imaginable, is the worst possible outcome for someone whose entire identity is built on the uselessness of their research. The man's scream of anguish at learning his work is useful is a perfect inversion of normal expectations.
References
The divide between pure and applied mathematics is a long-standing cultural tension in the field. The famous pure mathematician G.H. Hardy wrote in A Mathematician's Apology (1940) that he had "never done anything 'useful'" and considered this a point of pride. Ironically, Hardy's work in number theory later became foundational to cryptography and internet security. Homeomorphic function construction refers to a concept in topology, one of the most abstract branches of mathematics.