Based on the Auton's from Doctor Who
The Cardoc's are metal based with some plastic and silicone parts and a leather like innareds. They can shape shift into various things that have their genetic composition to blend in. These are the things that The Janitor, Dana, and Jacob first encounter amid the their dating excapades. Forcing The Janitor to come out of his secrecy and be honest with the both of them. So on one of their last days of dating separately he told them everything about himself and what he is. They started dating together and he told them about what he does for a living and his real age which is 619 year's old but explained to them that his species ages differently than humans do and what he does for a living saving people. They wondered if that's what they'll be doing and The Janitor confirms this by stopping a cardoc from following them.