Bossy boy

Kyler has recently entered a new "bossy stage".  His victim? 

Poor dog.

Kyler LOVES scaring the dog. He thinks it's funny. See that lawnmower in the picture above? Bauer is terrified of it. What does Kyler do? He chases the dog around with it, and tries to herd him into places he wants him to go. He does the same thing with other toys that Bauer is scared of inside (basically any toy that makes noise) and then he herds him into the playroom, or shuts him in the laundry room etc. If Kyler doesn't have a toy? He uses a stick, or just simply grabs the dog's collar, and bosses him. Bauer is probably 4 times the size of Kyler, but he is so submissive he just does whatever Kyler tells him to with his tail tucked between his legs.

It's as if Kyler can't resist. I don't know if he just gets a thrill out of making something bigger than him do what he wants, or what. I can't figure it out. I correct his behavior whenever I see him scaring Bauer, but still, every time Kyler think's I'm not looking he is constantly bossing the dog around. Should I be worried? Bauer has never shown any signs of being aggressive, but still I just don't understand why Kyler likes making the dog so miserable.

Hopefully this phase won't last very long, and they will go back to being buds.