Parasitic flatworms (Leucochloridium paradoxum) attack innocent gastropods, and force the snails to feed themselves to birds - over and over. While you ponder the Prometheus-like fate of these snails, let's first talk about Toxoplasma Gondii, which infects human beings.
In a previous article (Toxoplasma Gondii Parasite Mind Control) I detailed the peculiar facts about Toxoplasma, which is found in the gut of cats. The parasite sheds eggs, which are then picked up and eaten by rats. The rats remain perfectly healthy. Or do they?
It turns out that the rat brains are subtly altered. Instead of fearing places where cats hang around, the poor rats actually come to prefer places where cats spend a lot of time. These rats are more likely to be eaten by the cats, thereby completing the lifecycle of the Toxoplasma parasite.
Human beings are also infected by the parasite; about half of the people on Earth have had an infection. Researcher Fuller Torrey noticed a number of links between Toxoplasma infection and human neurology and behavior. Read the article for details.
What Toxoplasma gondii apparently does to people is disgusting. However, it's nothing compared to the fate of poor snails. I commend the following video to your attention.
I thought that Toxoplasma forming tiny cysts in my brain and spreading throughout my nervous system was bad. As this video proves, it can always get worse.