My best guess: Gray Treefrog Fact Sheet - Signs of the Seasons: A New England Phenology Program - University of Maine Cooperative Extension
It is a reptile, not a toad as the name implies. Form Wikipedia: Horned lizards (Phrynosoma), also known as horny toads or horntoads, are a genus of North American lizards and the type genus of the family Phrynosomatidae.
Nice! I had a similar experience - in a public campground shower. Mr. Froggy was resting on top of the shower head.