A louse that has infested clothing or linens. Typically used in the plural. No way am I staying in such a crappy motel! Their beds are probably crawling with seam-squirrels! Our uniforms were so thoroughly infested with seam-squirrels that there was nothing left to do but burn them.
n. lice. (see also pants rabbits. Contrived.) I got an itch. Must be seam-squirrels.