I was looking for a video, but found this:
What is a mic drop statement?
A mic drop is the gesture of intentionally dropping one’s microphone at the end of a performance or speech to signal triumph. Figuratively, it is an expression of triumph for a successful event and indicates a boastful attitude toward one’s own performance.
https://www.thehouseofsolidgold.com/what-is-a-mic-drop-statement/
Then found a video referencing Joe Rogan (I won’t link the 0bama video):
https://citizenfreepress.com/column-1/black-ufc-fighter-epic-mic-drop-on-joe-rogan/
(language warning, but apropos)
Sounds more like he fumbled the mic like dropping the ball. Stupid expression.