There are innumerable interesting creatures in the world. They never fall short of fascinating us by their unique and unbelievable characteristics that may involve their dynamic physiology, preying style, camouflage techniques, ways of finding hosts, life cycles, feeding, etc. Sometimes these interesting details might get pretty weird because, of course, not all species prefer living as sophisticated as we do. Parasites and fungi are some of the most common examples of organisms that manage their lives in a very strange and bizarre fashion, sometimes so unusual that it sounds completely unreal. Believe it or not, that’s nature, and so here is the list of 10 such parasites and fungi that you wouldn’t believe exist

1 Leucochloridium is a parasitic worm that will first make itself attractive to a snail’s eye by pulsating to appear like a caterpillar. Then the worm will make its host wander in the open by controlling its mind for birds to attract and feed on its eyes. The worm will then breed in the bird’s gut and lay its eggs in the bird’s feces, which will eventually be eaten by another snail and the cycle continues. 

These species fall under the category of flatworms. In appearance, the worm has brood sacs composed of green bands with dark brown and black spots. The brood sacs on the worm’s body pulsate heavily when it captures the snail’s eye to make an appearance like a caterpillar or grub.

It pulsates more rapidly in the sunlight, and when it becomes dark, it does not pulsate at all. The worm also controls the body of its hosts and directs its behavior that will attract hungry birds. The infected snails spend more time in lighter places, higher altitude vegetation, and become more mobile. 

When it enters the bird’s body, it reproduces and lays eggs that are released through the excretory material which is in turn consumed by snails, and thus the bizarre life cycle continues. The worm imitates to appear like the host’s food to enter into the host’s body.

This technique is known as “aggressive mimicry” and is used by many other parasites as well.

Moist areas like marshes are the places where these flatworms are generally found. (1, 2)

2 Cymothoa exigua, also known as the “tongue-eating parasite,” lives in a fish’s mouth by replacing the fish’s tongue after entering the fish’s body through its gills. The parasite first cuts off the fish’s tongue by breaking the blood vessels and then becomes the fish’s new tongue by attaching itself to the remaining stub of the tongue. 

Only the females are tongue-eating parasites. The male parasites usually attach themselves to the gills of the fish present behind the tongue where the female resides to reproduce. The parasite severs the blood vessels in the tongue of the fish with the help of its front claws causing the tongue to fall off.

The parasites have not shown any traces of causing other damage to the host’s body except replacing their organs and in some cases cause fish to lose weight. When the fish dies, the parasites detach from the tongue leaving a cavity in the mouth and then stick to the host’s head.

The reproduction process is more interesting than this. Every parasite is male before entering its host’s body, but when they successfully enter into a fish’s body, one attaches itself to the tongue and transforms into a female.

The other parasites that attach to the gills remain males. The same happens if there is already a parasite present in the tongue. This is a theory proposed by Colt William Cook in 2012. (1, 2)

3 A unique species of fungi named Radiotrophic fungus were discovered at the Chernobyl Nuclear Power Plant and exteriors of the low Earth orbit spacecraft that use gamma radiations as the source of nutrition to grow.

These fungi are single-celled organisms and were found in extreme conditions. These fungi show rapid growth after coming in contact with gamma rays and not just that, gamma rays also made them faster and they grew in the direction of the radioactive particle sources. 

Scientists have named this newly found phenomenon “radiotropism,” which means the growth of these fungi in the direction of ionizing radiations. Just the process of using melanin and radiation as energy is termed “radiosynthesis” and categorized as a type of anaerobic respiration.

However, the scientists are not sure whether or not these microorganisms use other sub-processes such as photosynthesis and chemosynthesis to complete radiosynthesis. 

The radiotrophic fungi were first discovered in the Chernobyl Nuclear Power Plant in 1991, and since then it has been a subject of heavy research. The faculty still needs further examining, but it is hypothesized that these fungi could be possibly used in the form of a shield to protect the astronauts in space against radiation. (1, 2)

4 There is a fungus called Massospora cicadina that infects cicadas by replacing their genitals with the fungal stump. Then the pathogen releases chemicals found in hallucinogenic mushrooms called amphetamines and psilocybin to hijack the cicada’s brain. After getting infected, the cicada indulges in non-stop mating, transmits the disease to other cicadas, and eventually dies. 

The fungal pathogen only infects 13- and 17-year periodical cicadas. The infection replaces the genitals of the host also making it infertile. Once the parasite finds the body of a host, it then gradually releases chemical compounds to make the cicada go on a drug trip.

The host show very aggressive sexual behavior and sex binges. If the parasite finds a female host, it forces the cicada to flap its wings faster to attract males. Whichever it is, the host goes crazy and infects the other cicadas during the process, and eventually dies. 

The species were observed back in 1850 but were not described until 1879. They are mostly found, obviously, in the same habitats as their host cicadas, which are usually the large temperate zones. (1, 2)

5 Toxoplasma gondii is a type of single-celled protozoa that first enters into its intermediate host, which is generally a rodent, and alters its neurology so that the rodent becomes less fearful or possibly sexually attracted to domestic cats. The protozoa reproduce into the cat’s intestine after the cat consumes the rodent and the offspring are dropped along with the cat’s excretion which is eaten by rats to complete the cycle.

The protozoa are found in one-third of all organisms and apparently in the heads of all warm-blooded animals including humans. The primary host of the protozoa is only the domestic cat which it uses as the home for asexual reproduction and to reach into the intestine of the animal, the protozoa attaches inside the brain of its intermediate hosts and alters their neurology to reach their original destination.

For example, if the parasite is in a rat, it affects its neurochemical pathway such that the rat will lose the fear of cats or rather become sexually attracted to them. The host rat now becomes easy prey for cats.

Once a cat eats the rat, the protozoa reach their breeding destination where it reproduces. The offspring are released with the urine and excretory material of the cat which is in turn eaten by other rodents and rats so that the protozoa can again repeat the same. 

Besides its weird lifecycle, scientists have discovered that it also affects the way we, humans think, affect sour personalities, alters our behavior, and might also play a role in cross-cultural differences. (1, 2, 3)