Cellar spider (likely long-bodied cellar spider)

Common indoors in quiet, dim, humid areas such as window corners, basements, garages, and ceilings; it often builds webs near openings.

Predatory, feeding on flies, mosquitoes, moths, mites, and other spiders caught in its loose, irregular web.

It vibrates rapidly in its web when threatened, making its body difficult to see. Females carry egg sacs in their jaws, and adults may persist indoors year-round.

Harmless to people and pets; its bite is extremely unlikely and medically insignificant. It benefits homes by consuming nuisance insects and occasionally other spiders.