It’s known as a jaw harp, or Jew’s harp, or juice harp, or mouth harp, or ozark harp, or trump, or guimbarde. Yes, that many (probably more) various names for the instrument.
So how can it be taken seriously with so many names? How can it be taken seriously when it sounds so funny and is played basically by making a “twang-a-lang” sound inside your mouth?
But it makes for a good laugh. Oh, and I’ve personally owned a jaw harp for at least 15-20 years. But I gave up learning because I didn’t know how it was supposed to be played… sheesh.