To keep it REALLY short. A Marisa and Reimu try to get in, and get chased off many times. First he sics his corgi on them. Second he lets them in to avoid the rain because they make a lot of noise knocking on his door. Third is his cat while his corgi is asleep. Fourth is when they're cornered by the cat and dog, so he picks them up and throws them far away.
The final time, they see him preparing a peel by peeling some food, and thinks he's going to eat them, so they run away.