ABANDONED. children's book about exaggerating squirrel sighting

[Corey]

I had a kid's book that was about a boy who sees a squirrel in his yard and goes in to tell his parents. Between seeing the squirrel and reaching them he begins to exaggerate his sighting in his head to the point that, when he reaches his parents, he begins describing a weird animal (square I think) that has never existed.

[Kris]

Corey, around what year did you read this book?

Is this a picture book or chapter book?

What type of illustrations - cartoony, realistic, painted/watercolor, black-and-white/sunny/dark/muted, etc.?

[Corey]

Picture book with simple illustrations (maybe drawings with a little color?). I read it in the early 60s.

[Lobstergirl, au gratin]

Corey left the group. Moving to Abandoned.