Baby's Name Is?

Liam, like most kids, has picked up a collection of nicknames in his two years of life. I call him "Baby Boy" or "Tiger" or "Sweetie Pie" or "Kiddo". Since he began speaking, Liam has referred to himself as "Baby", and very occasionally, "Weem."

Then, a few weeks ago, he was marching down the stairs and yelling "BOOM!" on every step. He became known as "Boomer" for a short while.

But, as of yesterday, he has yet another name. He was scooting across the floor on his backside, so I addressed him as "Scooter."

Liam: "Baby not 'Cooter."

Me: "Hhhmmm. Then are you, maybe, Boomer?"

Liam: "No. Baby's not Boomer."

Me: "Oh. I know, your name is, um, CASEY!!!"

Liam: "Nope. Casey is big black crazy dog. On sofa."

Me (noting muddy pawprints on sofa): "Yup. That's him. So, what's your name, kiddo?"

Liam: "Come, Mommy! Baby does have new name! Baby not Boomer! Baby not 'Cooter! Baby call self new name...Baby's name is 'Cooter, um, puh, um, 'Cooter Pie! Baby call self 'Cooter Pie!"

So Liam is now officially Scooter Pie. I can't figure out where he came up with this name. Maybe he hybridized "Scooter" and "Sweetie Pie?" However he did it, I'm pretty sure he's never seen one of these.