This big prehistoric-looking bug is walking on my ceiling. It has weird flared back legs and looks intimidating. Is it going to bite?

bugs.

The Western Conifer Seed Bug, scientifically known as Leptoglossus occidentalis, is a member of the Coreidae family. This bug is often mistaken for other, more harmful insects due to its size and appearance. Adult Western Conifer Seed Bugs typically measure about 16 to 20 mm in length, making them one of the larger bugs that might find their way indoors.

Native to the western United States, these bugs have expanded their range significantly due to human activity and are now found across much of North America and even parts of Europe. Their bodies are elongated and flattened, with a distinctive brownish color that provides excellent camouflage against tree bark. Their most notable feature is their hind legs, which have a leaf-like expansion that contributes to their prehistoric appearance.