"I didn't realize tortles could grow body hair..."
"They can't."
"But--"
And then the student will inevitably notice the strap attaching Professor Jum's fake beard to his bald turtle head and everything becomes clear. Ish. Why does Professor Jum wear a fake beard to class everyday? No one really knows. Maybe he's hiding some hideous deformity. Maybe he's got a secret stash of Feydust underneath that he snorts in class. Or maybe he just likes the way he looks with a beard. Who can tell? All the students know is that he never seems to take it off, even when it is clearly itching.