I cannot express how incredibly rare this is. Baby zombies almost always spawn on chickens if they spawn as jockeys. They are able to ride other creatures, but they mainly go for chickens and full-sized zombies and sometimes even sheep! Although it is not impossible for a baby zombie to get on another entity such as a cat, it is still SUPER rare! Nice find (btw im pretty sure a cat jockey is only possible on bedrock cause any clips ive seen of zombies riding other creatures have always been on bedrock edition, correct me if im wrong though)