A "preposition" is grammatically anything a frog can do to a toadstool. It can be on a toadstool. It can be under a toadstool. It can be around the toadstool. It can be...a toadstool? Yes. Yes it can. But that's just a standard present tense verb with a third person singular subject. So.

frog, mushroom, toad, red, orange, spot, polkadot