I just spotted a creepy, many-legged crawler racing across my basement floor, complete with ridiculously long antennae. It looked like something prehistoric. Should I be concerned, or is it just unsettling to look at?

That fast-moving, many-legged creature you spotted in the basement is most likely a house centipede — a bug that looks terrifying but is usually harmless to people. With its long antennae, dozens of legs, and lightning-fast movements, it can seem like something out of a prehistoric nightmare. But despite the creepy appearance, house centipedes are actually helpful hunters that feed on pests like spiders, cockroaches, termites, and silverfish.

They’re drawn to damp, dark spaces such as basements and bathrooms because that’s where their prey tends to hide. Although they do have venom to kill small insects, they rarely bite humans, and when they do, it’s typically no worse than a mild sting.

If you’d rather not share your home with them, reducing moisture, sealing cracks, and keeping the area clean can help discourage them from sticking around. Still, many people tolerate them because they quietly help control other unwanted bugs.