This frog defies gravity with diamagnetic levitation. Many materials that we ordinarily think of as non-magnetic can be manipulated using magnetism.
It's easy to show that grapes are diamagnetic--just see this Exploratorium snack. For an explanation of diamagnetism, see the text at the end of the snack.
You may have seen the Levitron, the spinning and levitating top, in a physics classroom before. Read about how it works here.
