Violent kid?

RyanC was hugging and kissing baby AidanC while I held AidanC and sat on the sofa. All of the sudden RyanC stopped, looked me, and he started hitting my arm a few times! He then attempted to hit baby -- but missed. WHOA!

He has been doing this in the past 2 days but not often. We have no idea how he learned to hit people. We speculate he might be getting jealous of us holding AidanC all the time. I am not sure how to get him to stop though...

Tonight I handed baby to wife and then gave RyanC big hugs. He didn't try to hit us after that but he twisted to get away from me hugging him. We then spent the next 10-15 minutes chasing each other around the house. Maybe I need to play with RyanC more often....