THe ball uses the 'Throw item" mechanic of the game, which is usually intended for things like flasks, boxes, rocks, crates, etc. In other words, as an attack. Which explains why your companion feels like you attacked them. Basically the game treats it like you are not passing the ball to them, but that you are trying to attack them with it.
Oh I totally understood WHY he attacked me. It just surprised me considering the interaction with the npc is designed around that action and that particular item. So when I threw it at Wyll I assumed there was an exception condition with that one particular item to not consider it as an attack. Nope. From quiet night to suddenly dog pile on Wyll with every range attack spell possible. (pun intended and that particular combat he rolled really low on initiative and thus went last. heh.)
I haven't managed to get the owlbear cub into the camp yet. Haven't touched the goblin camp yet, but I'd hope some interactions between Scratch and the cub as well..
