Growling and waving, waving and growling

I have been trying to catch Parker growling on camera for weeks. He does this growling sound all the time and it is so cute. If you say, "where's the monster?" he starts crawling towards you and growling. I finally caught it! After I got lucky with the growling sound I tried to get a few of their new words/sounds out of them but they just wanted to wave at me...