Say... it's a Sey egg! Sey eggs have a deceptively shiny appearance, but are very rough and scaly to the touch.
Sey are very perceptive creatures, wise, and discerning in all situations. As a result, they do not find themselves in dangerous situations frequently. If they do, they know how to escape. In their first, younger stage, they have one set of unique antennas that give them a strong sense of hearing. These antennae disappear in the adult stage, but Sey's ear drums become even more sensitive to noises. If your Sey is far away, just say the word and they will be there.