MY STUDENT (on way out of lesson): Look out, we're about to get blocked in by tympanis!
ME: It's not "tympanis." "Tympani" itself is plural; the singular is "tympanum."
TYMPANIST: Wow, I feel like such a bad tympani player for not knowing that.
(I also found through some quick research that another singular form is "tympano." And I informed the tympanist that both "broccoli" and "graffiti" are also plurals, but you knew this if you've been reading this blog for a while.)
The best word that could be used to describe today: ARRRRRRR.