Booklouse (likely)

Moist indoor locations, especially books, cardboard, cupboards, textiles, and areas with condensation. They may occur on grooming tools or other stored household items.

Molds, fungi, algae, microscopic organic debris, and sometimes starch-based residues. They do not bite or feed on healthy human tissue.

Pale, soft-bodied, wingless insects that move quickly and favor darkness and humidity. Populations increase in damp, poorly ventilated conditions and decline when items are dried.

Generally harmless to people, pets, and structures, though large numbers can contaminate stored products or indicate excess moisture and mold. They contribute modestly to decomposition and microbial turnover.