Where do you draw the line on what can be considered a pet? Stephen here has a magical, animate cloak that behaves similarly to a living creature (that is, it acts independently of him and it chose him as its owner). If it's allowed as a pet I would expect to nerf its abilities, as it normally allows him to fly and is normally strong enough to block bladed weapons without being damaged itself. Let me know if this is even within the realm of possibility, and I can get back to you with a specific nerfing proposal.