Fantastic, Frightening and Just Plain Weird Fungi

Forget ghosts, vampires and things that go bump in the night. This Halloween, some of the strangest – and most interesting – characters are hiding in the forest.

The fungal kingdom is filled with organisms that glow in the dark, smell like rotting flesh, resemble bloody teeth and even turn insects into “zombies.” And unlike the monsters in your favorite horror movie, these creatures are very real. 

In honor of spooky season, meet a few fungi that prove nature has quite the imagination – and deserves the utmost respect from us.

One important note: Wild mushrooms can be difficult to identify, and edible species can have toxic look-alikes. Unless you’re an experienced forager who can positively identify a mushroom, don’t eat it. For the fungi on this list, think: look but don’t touch.

Devil’s fingers look ready to grab you

Imagine walking through the woods and spotting bright red tentacles emerging from what looks like an egg. Meet Clathrus archeri, commonly known as devil’s fingers or octopus stinkhorn.

The fungus begins inside a whitish, egg-like structure before several red arms emerge. As if its appearance weren’t creepy enough, those tentacles become coated in dark, sticky, spore-containing slime – and smell like rotting flesh. The revolting odor attracts flies and other insects, which pick up the spores and help disperse them.

As for putting it on your plate? Devil’s fingers is generally considered inedible or of no culinary value, and that foul odor probably won’t leave you tempted. This is one to admire, photograph and leave where you find it.

Devil’s tooth appears to bleed

At first glance, Hydnellum peckii looks like something that should require immediate medical attention.

Young specimens of this fungus can develop striking red droplets against a pale surface, earning it names such as devil’s tooth and bleeding tooth fungus. As the fungus matures, the droplets disappear and its appearance changes.

Underneath that horror-movie exterior is an important forest relationship. Devil’s tooth forms mutually beneficial associations with certain trees. The tree supplies sugars created through photosynthesis, while the fungus helps its partner access water and nutrients.

Devil’s tooth isn’t edible, so resist any curiosity about those red droplets. This is another mushroom to admire, not collect.

Dead man’s fingers live up to the name

You probably don’t want to see fingers reaching out from beneath a fallen tree. Unfortunately, Xylaria polymorpha likes giving hikers and foragers a good jump-scare.

Commonly called dead man’s fingers, this fungus forms dark, finger-shaped structures that can appear in clusters around decaying wood. They can look uncannily like something – or someone – trying to claw its way out of the forest floor.

Despite the sinister appearance, fungi like these have an important job. By breaking down dead and decaying material, decomposer fungi help recycle nutrients through the ecosystem.

Dead man’s fingers aren’t edible. (Noticing a trend here?) Consider those creepy fingers strictly a look-don’t-collect addition to your forest walk.

Some fungi serves as nature’s nightlights

A glowing mushroom sounds like something from a fairy tale, but fungal bioluminescence is real. More than 70 species of fungi are known to produce their own light through chemical reactions. The phenomenon is sometimes called “foxfire,” and depending on the species, the glow may come from the mushroom, its mycelium or both.

Jack-o’-lantern mushrooms are among the most famous examples. Some species in the genus Omphalotus can produce a greenish glow from their gills – an especially appropriate trick for a mushroom named after a Halloween tradition.

But don't let their festive name tempt you. Jack-o’-lantern mushrooms are poisonous and should never be eaten. They can cause severe gastrointestinal illness and may be confused with edible mushrooms such as chanterelles by inexperienced foragers. Once you know the difference, you’ll never confuse them. If you’re a newbie, know this: You’ll never stumble into chanterelle patches as thick as a cluster of jack-o’-lanterns.

Admire their glow and take some photos, but leave the mushrooms exactly where you found them.

“Zombie fungi” sound like science fiction

If you’ve watched The Last of Us, this one may sound familiar. Certain fungi in the genus Ophiocordyceps parasitize insects and other arthropods. Some can manipulate their hosts’ behavior in ways that help the fungus reproduce. An infected insect may climb and attach itself to vegetation before dying, after which the fungus can produce spore-releasing structures from its body.

It’s an astonishing survival strategy – and one that has nothing to do with the Cordyceps mushrooms you know and love. The good news for your Halloween plans? These fungi have evolved relationships with particular insect and arthropod hosts, not humans.

And if you’re lucky enough to encounter one of these fascinating relationships in the wild, leave the scene intact. This is something to observe and photograph, not collect.

We’re still discovering how weird fungi can get, and scientists continue to identify new fungal species. With an estimated 5.1 million species and counting, much of the fungal kingdom remains undocumented. Which means there are almost certainly plenty more freaky fungi out there.

Photo credit: Nikola Tomašić