Blue-headed Bull Frog
About 6 years back, I found what looked like a regular bull frog, but it had a blue head instead of a green one. I found it in a small pond in the U.P. Of Michigan. I never took a picture of it (didn’t think of it), and haven’t been able to find anything about it online. It’s been bugging me since, I just HAVE to know what it is!
Sometimes frogs & other animals have color abnormalities (e.g. albino). It's not a separate species or anything like that.