a spider with a skull on its back
Steatoda nobilis Steatoda nobilis has a brown bulbous abdomen with cream coloured markings that are often likened to the shape of a skull.[7] The legs are reddish-orange.[8] Females range in size from about 9.5 to 14 mm in size, while males are 7 to 11 mm.[1] Males are able to produce stridulation sounds during courtship[citation needed], by scraping 10-12 teeth on the abdomen against a file on the rear of the carapace.