Speedy has a small "irregular" spot on the back of his carapace . I have heard it referred to as an "egg bump" . like maybe they laid that way while the shell was forming inside the egg . Anyway , its just a minor deformity and is not really harmful . Think of it as an I.D. marker if he ever makes the Great Escape and you have to identify him !
I can't find a pic where it is really noticable , but it is in this circled area . Hope that helps .