How did a squirrel get in my toilet?

Squirrels can sometimes live in walls and can possibly spot the toilet, see water and go over to drink, possibly falling in. OR if you have a dog or cat and the squirrel is dead, the animal could have carried it in and somehow dropped it in the toilet. Though it can always be someone playing a prank on you...I've had a dead squirrel put in my cereal box by my brother, so it is more possible than the other two theories!