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Many alarming-looking arthropods are low-risk to people in ordinary encounters, but “harmless” does not mean every species is safe to handle or has no effect on a home or garden. This list explains what may look frightening, what to watch out for, and when to leave an animal alone or ask for local identification help.
Appearance alone is not a reliable danger test. Do not touch an unfamiliar arthropod, especially one that resembles a wheel bug, assassin bug, bee, or wasp; some can bite if handled. The University of Maryland Extension and other regional extension services can help identify uncertain specimens.
14 scary-looking bugs and what to know
| Arthropod | What may look alarming | What to know and do |
|---|---|---|
| House centipede | Many long legs and fast movement | Maryland Extension describes house centipedes as predators of indoor insects and spiders. They are startling, but their presence is not evidence they are hunting people. If one is indoors, escort it outside. |
| Harvestman, or “daddy longlegs” | Very long, thin legs and a spider-like appearance | Harvestmen are not spiders; their body is fused rather than divided into two main sections. The University of Georgia Extension says they cannot bite and are harmless. Common names vary by region, so do not apply this identification to every animal called “daddy longlegs.” |
| Millipede | Many legs; some gather or coil when disturbed | Millipedes are associated with damp places and decaying plant material. The University of Georgia Extension notes they may coil or release an unpleasant odor when threatened and usually dry out indoors. Reduce excess moisture and remove them without handling. |
| Pillbug or sowbug | A segmented, armored-looking body; some roll into a ball | These moisture-dependent arthropods are common in damp areas. Maryland Extension says they die quickly indoors. Sweep up indoor visitors, reduce excess moisture, and consider exclusion if they keep entering. |
| Springtail | Tiny bodies that jump suddenly, sometimes in groups | Springtails commonly appear in humid locations such as bathrooms or around flowerpots. Maryland Extension recommends reducing excess moisture and cleaning mold or mildew rather than reflexively spraying. |
| Silverfish or firebrat | A flattened body with three tail-like appendages | These are not a reason to panic about human danger, but they can damage household materials. Maryland Extension and its indoor-insect resources note that they feed on starchy materials, including paper, book bindings, dry food, flour, and cloth. Identify and manage them if you find repeated activity or damage. |
| Earwig | Pincers at the rear of the body | Earwigs occasionally enter homes and can be escorted outdoors, according to Maryland Extension. The pincers look threatening, but they are not a reason to assume the insect poses a serious danger to people. |
| Clover mite | Very small reddish-brown body and conspicuously long front legs | Clover mites live primarily in lawns and feed on grass. They may crawl up sunny sides of buildings. Maryland Extension suggests vacuuming indoor mites and excluding them around openings. |
| Boxelder bug | Red-and-black coloring and large gatherings on sunny walls | These are nuisance invaders that may enter buildings. Maryland Extension advises exclusion and vacuuming indoors; it says outdoor control is not needed. |
| Multicolored lady beetle | Variable orange-to-red coloring and occasional spots; groups near sunny windows | Maryland Extension recommends sweeping them up and releasing them outdoors. They also prey on aphids, so avoid unnecessary control. |
| Wheel bug | Large body, cog-like crest, and beak-like mouthparts | Wheel bugs are predators of soft-bodied insects and can be beneficial in gardens. The University of Kentucky Extension warns that they can deliver a painful bite if handled. Observe from a distance and leave them alone. |
| Assassin bug | Long, narrow head and body, a distinct “neck,” and a pronounced beak | Many assassin bugs prey on other insects. Maryland Extension cautions that large species can bite people. Keep your distance and seek local identification if you are unsure. |
| Wheel-bug and assassin-bug lookalikes | Gangly legs or a spider-like outline | Some predatory insects can be mistaken for other arthropods. NC State Extension notes that assassin bugs’ legs and antennae can contribute to a spider-like appearance. Do not handle a specimen based only on a generic resemblance. |
| Unidentified household arthropod | Unusual shape, sudden movement, or a large number appearing at once | A general list cannot reliably identify every regional species. Take a clear photo without touching it and consult a regional extension identification service if the animal is associated with bites, damage, or persistent sightings. |
How to respond to a frightening-looking bug
- Keep people and pets away. Do not handle an unknown animal or let a pet eat it.
- Observe without touching. Note its shape, markings, location, and behavior. If safe, take a clear photo from more than one angle.
- Remove low-concern indoor visitors without spraying by default. Sweep or vacuum them, or use a container and stiff paper if you can do so safely.
- Address the conditions that attract them. Reduce excess moisture, clean mold or mildew, and seal likely entry points where appropriate.
- Ask for expert identification when needed. Seek help for a bite, suspected sting, repeated sightings, household-material damage, or uncertainty about a potentially defensive species.
When is a bug harmless—and when is it a problem?
Low risk to people does not necessarily mean no impact. Harvestmen are harmless according to the University of Georgia Extension, while silverfish and firebrats can consume household materials. Wheel bugs and some large assassin bugs are predators but may bite if handled. Identify the animal and consider where it was found before deciding how to respond.
FAQ
Are all scary-looking bugs harmless?
No. This article covers examples that are generally low concern in ordinary encounters, but lookalikes and regional species can differ. Do not handle an unidentified arthropod.
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Can a wheel bug or assassin bug bite?
Yes. The University of Kentucky Extension warns that wheel bugs can give a painful bite if handled, and Maryland Extension cautions that large assassin bug species can bite people. Observe them from a distance.
Should I spray when I see one of these arthropods?
Not automatically. Extension guidance includes escorting, vacuuming, releasing, exclusion, and moisture reduction. For silverfish or firebrats, check for household-material damage and use identification guidance to choose an appropriate response.
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When should I contact an extension service or pest professional?
Ask for help when an arthropod may have caused a bite or sting, when sightings recur, when household materials are being damaged, or when you cannot distinguish it from a potentially defensive lookalike.
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