Dirk the Daring sends in this one. The basic joke is just that Hagar messes up. But the details? Did he try to eat it? Did he impale himself on it? Did it get stuck in his beard? (but an internet search on “images violinists with beards” returns a lot of violinists with far longer beards). What’s the situation in that last panel?
And, if you dare, how would you stage that last panel?