So I was outlining the part of the story where Gyvaris, a dragon, almost gets killed, when I realized I glanced over something. You see, Gyv had a human friend before and they used to play games to pass time.
Gyvaris' mother taught him the basics of close-quarters combat through various games. She'd often throw various items towards him, telling the young dragon to catch them with his mouth. If Gyv was too slow or overextended, he couldn't reach the next one in time.
Though Gyv had learned how to strike at blinding-fast speeds, he also tends to damage whatever he catches. I mean, he has the jaw-strength of a Nile crocodile. This is fine when fighting dragonslayers or catching the chunks of meat that his mother tossed into the air, but kind of ruins a casual game of catch.
Plus there's Gyvaris' battery-acid-breath weapon. It's life-threatening when inhaled, can cause chemical burns on the skin and blindness when it gets into the eye. Gyv doesn't drool often, but the residual acid in his mouth can still cause toys to deteriorate.
Dragons are pretty big, at around 6-10 metres in length (ridiculously long tail included) and two metres at the wing's shoulders.
So, if the dragon is regularly playing games of catch with a human, how could the human make a toy for the dragon that can last for a while? It doesn't have to be fancy, just safe, durable and usable.
Tech-level is medieval.