Goom-ba and Pik-caw

These are a couple of Ben-isms that we've yet to identify. I had to write them down before the years passed and I completely forgot them.

"Goom-ba" has been a favourite of Ben's for many months now, perhaps since he was about 8 months old. He says it with less frequency these days. His new favourite appears to be "pik-caw"... whatever that means. I keep asking him to "show Mommy pik-caw?" but he just looks at me blankly and reiterates "pik-caw!" I may never know.