So we have our scarab who is a doctor, and specifically they appear to be a pharmacist — pill roller being another term for pharmacist. Where the pun comes in is they are identified as a scarab aka a beetle — which is accurate, scarab is a family of beetles — aka a pill roller. Except the bug the book is trying to reference is called a pill bug or a roly poly, not a pill roller. Now I will give Ende the benefit of the doubt and assume that aspect of the pun actually works in the original German. But he’s not off the hook. Not only is a roly poly not a type of scarab, it’s not even a beetle. Roly polies are woodlice, which are a type of crustacean (apparently).