The bright red spot was a mushroom. It was so red that I thought to myself: "That thing must be very toxic." When I got back home, I looked it up in our Champignons book. It's called an Amanite tue-mouches in French. It's called "fly agaric" in English.
According to the book, its white flesh is highly toxic. The English Wikipedia calls it "poisonous and psychoactive" — it is "famed for its hallucinogenic properties". Here's a link to the article. The fly agaric has also been used as an insecticide. Its flesh, sprinkled in milk, attracts and kills flies.
The French Wikipedia article says "druids and sorcerers" used to use the Amanita muscaria mushroom the way peyote is used in Mexico, to provoke religious experiences. It was similarly used in eastern Siberia up to the 19th century. You can chew the mushroom or soak it in milk, hot water, or blueberry juice to release its active ingredients.
I won't be trying that. Food in fluorescent colors doesn't really tempt me — not to mention the insecticide angle. It seems this quintessential "toadstool" grows quite commonly in the Northern Hemisphere, but I don't think I've ever seen it before.
Quite often, our sunsets here at La Renaudière are quasi-hallucinogenic experiences. The other pictures in this post are ones I took yesterday afternoon, right after seeing that mushroom. I said "seeing," not "eating."
* * *Here's a picture of the thing that fell off my car. It was hanging by a single screw under the engine compartment until yesterday afternoon, when I took a screwdriver to it.
Now I need to take it to the mechanic and ask him to re-attach it if he thinks it serves a real purpose. It's a sizable piece of plastic.