Bed bug

Mattresses, bed frames, upholstered furniture, cracks, and other sheltered indoor locations, especially near sleeping hosts.

Obligate blood-feeder, primarily consuming human blood but sometimes feeding on bats, birds, or other mammals.

Mostly nocturnal and attracted to warmth, carbon dioxide, and host odors. They hide during daylight, reproduce in sheltered crevices, and can survive months without feeding.

Bites cause itchy welts and occasional allergic reactions, but bed bugs are not known to transmit diseases reliably. They are household pests with no meaningful ecosystem benefit indoors.