Unidentifiable insect/speck (likely Carpet Beetle Larva or Booklouse)

Typically found indoors on organic fibers, near books, papers, or stored dry foods.

Depending on the species, could eat keratin (wool, hair), starch (glue, paper), or mold.

Often found in dark, undisturbed areas; larvae may be slow-moving; booklice are quick moving.

Generally harmless to humans (no bites/stings), but can cause allergic reactions or damage property like fabrics and books.