Can an artificer cannon move through a creatures space? [closed]

Okay so a tiny cannon does not occupy a space, so in my eyes it can move through the legs of creatures, right? Given there is actual space there. Like a rat would do. I suppose the cannon is 0.5 – 1 feet?

Last session we ruled that it could move through the legs, I had to move it through the 4 square occupying bear druid. But my GM said it could not attack while being in someones space, so I had to actually move it through the bear, over to me, then pick it up, let it attack while I held it then put it back down again. But what difference does it really make? It would be more fun if it had some creative flexibility, like it could climb the bear druid and attack from it’s shoulders. It got crowded in melee range and it is tiny, so I don’t really see why it has to be in it’s own space or in my had to attack.