what are reasons Rep decides to have a mouth and what does it look like?

[[He doesn’t like having one, since it takes a long time to get him to have a nice, non-drippy one, and he finds a newly-formed mouth to be pretty embarrassing. However, he needs one when he wants/needs to eat or drink. If he ever had to say “aaah” for a doctor or smooch someone, it would come in too.

Anyway, here’s how he looks with a recently-formed, wide-open mouth.]]