Six spooky creatures to scare you this Halloween

Halloween is just around the corner, so we’ve asked the staff here at Cosmos to nominate their favourite scary creatures to share with you.

Irukandji jellyfish

Warning sign for marine stingers at a beach
Credit: Adam Kalaitzis / Getty

These tiny jellyfish, found in tropical waters including around northern Australia, carry a mean sting. Both the ‘bell’ (main body) and tentacles carry highly venomous stingers. Getting stung leads to the potentially life-threatening Irukandji syndrome, which includes symptoms of severe pain, muscle cramps, nausea and vomiting, difficulty breathing, and sometimes respiratory failure or cardiac arrest. The several Irukandji species are actually nowhere near as deadly to humans as the related box jellyfish Chironex fleckeri,but in some ways they’re scarier, as they’re so tiny – with bells only a couple of centimetres in length – and hard to see, with almost transparent bodies. If someone is stung by an Irukandji jellyfish, the first-aid protocol is: remove them from the water, clean the sting area by dousing with vinegar (if available) or seawater, and call 000.


Mouth of a lamprey
Credit: PEDRE / Getty

They may look like aliens, but lampreys are actually an evolutionarily ancient family of fish. The eel-like creatures don’t have scales, fins, or even jaws – instead, their circular mouths are lined with several rows of sharp teeth. Like sharks, their skeletons are made of cartilage, not bone. The lamprey hunts by stabbing its prey with its teeth and using its rough tongue to scrape away the victim’s skin and tissue to feed on its blood. Pretty scary if you’re a fish, but luckily lampreys aren’t very dangerous to humans. In fact, lamprey flesh is considered a delicacy in many human cultures.


Swan beating its wings
Credit: Antagain / Getty

Do swans make you think of fairy tales and graceful ballet dancers? You’re not alone, but the elegant birds also have a growing reputation for being a little dangerous. There’s Mr Asbo, the white swan who rose to fame in 2010 for attacking rowers on the River Cam in England, and the case of a US kayaker who sadly drowned after apparently being attacked by a swan. Swans have also been shamed for attacking and killing each other and, as introduced species, for damaging local habitat and ecosystems. So how scared should we be? Like many animals, swans can definitely become aggressive when they feel threatened or are protecting their young, so it’s probably best to give them a bit of space during nesting season.


Mosquito feeding on human blood
Credit: Scott Smith / Corbis Documentary via Getty

Often labelled the world’s deadliest animal, mosquitoes are estimated to kill a staggering 1 million humans per year. They’re not intentionally plotting against us, but their bites spread deadly infectious diseases such as malaria, Zika virus, yellow fever and Dengue fever. Malaria alone is estimated to kill over 400,000 people per year – mostly young children – a matter of major global public health concern. When a female mosquito bites a human to feed on their blood, she secretes saliva containing proteins that stop the blood from clotting too quickly. This saliva secretion allows pathogens carried by the mosquito, like the parasite that causes malaria or the viruses that cause yellow or Dengue fever, to infect the human. However, some have argued that we can’t exactly blame mosquitoes for being the “killers” behind deaths from these diseases, any more than we consider humans to be “killers” when we unknowingly transmit diseases like tuberculosis or COVID-19 to one another.

Group A streptococci

Micrograph of streptococci bacteria
Credit: Juan Gaertner / Science Photo Library via Getty

Specifically, the Group A streptococci bacteria that cause necrotising fasciitis, AKA “flesh-eating disease”. This rare but absolutely terrifying condition occurs when a wound allows bacteria to infect the fascia (the layer of tissue under the skin). The bacteria grow and release toxins and enzymes that essentially ‘kill’ the surrounding tissue (that’s the “necrotising” part – from the Greek word ‘necrosis’, meaning death). The infection can spread and kill more tissue quickly, leading to serious complications including sepsis and organ failure – so rapid diagnosis and treatment is key. Antibiotics to kill the bacteria and surgery to remove the dead tissue are the common treatments. Necrotising fasciitis can be caused by several different types of bacteria, but Group A streptococci are the most common. To keep yourself safe from this flesh-eating nightmare, it’s important to keep all wounds and injuries clean and covered, even if minor, and consult a doctor if in doubt.

Drop bears

Koala with sharp teeth
A rare photograph of a drop bear. Image credit: Frank Wouters / Wikimedia Commons

The Australian Museum (AM) website reports that drop bears (Thylarctos plummetus) are found in densely forested regions of the Great Dividing Range in south-eastern Australia, and possibly as far west as South Australia. Drop bears hunt by ambushing ground-dwelling animals from above, waiting up to four hours to make a surprise kill. Once prey is within view, the drop bear will drop as much as eight metres onto the unsuspecting victim. The initial impact often stuns the prey, allowing it to be bitten on the neck and quickly subdued. The AM says bush walkers “dropped on” by drop bears have injuries including lacerations and occasionally bites. Most attacks are considered accidental and there have been no reported fatalities. Having forks in your hair or Vegemite or toothpaste spread behind your ears is said to act as a drop-bear repellent, although there’s no evidence to suggest that any such repellents work.

Happy Halloween from Cosmos!

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