I call Korbin the big mouth frog because this is a common face for him to make. For those of you who haven't heard the joke about the big mouth frog here is my version:
One day a big mouth frog was hopping through the forest where he met a fox and said "Hi Mr. Fox, I'm a big mouth frog. I eat flies; what do you eat?"
The fox said "I eat rabbits."
The big mouth frog said, "Oh, that's nice," and he hopped along.
He came across a cow in a pasture and said "Hi Mr. Cow, I'm a big mouth frog. I eat flies; what do you eat?"
"I eat grass," said the cow.
"Oh, that's nice," and he hopped along.
The big mouth frog came across a snake slithering in the dirt near a pond and said, "Hi Mr. Snake. I'm a big mouth frog. I eat flies; what do you eat?"
The snake's tongue licked the air and said "I eat big mouth frogs."
The big mouth frog puckered his mouth together and said very quietly "oh........"
So there it is. It's funny to see it told because typically the person hearing the joke will kind of mouth the joke without knowing.