Firebrat (likely)

Warm, humid indoor areas such as bathrooms, kitchens, boiler rooms, and around heating appliances. It hides in cracks, insulation, and wall voids.

Feeds on starches, sugars, cellulose, book glue, wallpaper paste, fabrics, and crumbs. It scrapes food from surfaces rather than biting or sucking.

Nocturnal, fast-running, wingless, and covered with scales; it avoids light and heat extremes. Firebrats develop gradually through molts, with young resembling miniature adults, and can live for several years.

Harmless to people and pets and does not transmit disease. Large populations may damage paper, wallpaper, books, stored starches, or some textiles; ecological benefits are minor as decomposers.