cosmology-3
Explanation
A professor tells a PhD student she is confused: the student was on track for a PhD in cosmology but "just stopped working." The professor offers to give a lesser degree for the work completed but wants to understand why. The student simply says "I have my reasons." In the next scene, labeled "Later," someone at a bar asks the former student what they do for a living. The student dramatically declares: "MASTER OF THE UNIVERSE."
The joke hinges on the double meaning of "Master." In academia, stopping short of a PhD in cosmology (the study of the universe) would earn a Master's degree. So the student deliberately quit the PhD program to receive a Master's degree, specifically so they could truthfully and dramatically claim to be a "Master of the Universe" -- a phrase that normally implies great power and importance (as in the He-Man cartoon or Wall Street slang for powerful financiers). The student sacrificed a higher academic achievement purely for the sake of having an impressive-sounding title at cocktail parties. The professor's bafflement in the first half sets up the reveal that the student's "reasons" are entirely about the comedic value of the title rather than any practical consideration.