What in the world is in my African Dwarf Frog aquarium???

[alexis]

My roommate has a small aquarium with 2 African Dwarf Frogs and one male beta fish. The aquarium is filtered, with a few fake plants. The object is about the size of a popcorn kernel, light brown, and seems to have some swirlyish markings on the outside. My roommate noticed a few weeks ago that one of the frogs' belly looked a little big... she thought it might be pregnant? I have no idea how the mating/gestational business of these things work. So what in the world is in the tank?