Shell of medium size, 14 mm, claviform, turreted, solid, very high spire. Protoconch low, rounded, 2 whorls, smooth, 0.46 mm high, 0.54 mm wide. 8 teleoconch whorls. Suture distinct, slightly undulating. Sculpture complex, dominant feature is up to 8 strong, broad axial ribs per whorl, begin just below upper suture, extend to lower suture, greatest at midwhorl. Ribs extend most of the distance down the body whorl, do not form varix. Distinct marginal spiral cord just below suture on each whorl; 4 spiral cords cross ribs on upper whorls. About 16 spiral cords on body whorl, sometimes with a single low ridge between cords. Outer lip slightly thickened but broken in holotype. Subsutural sinus present but depth cannot be determined due to chipping on lip. Slight callus. Columella smooth, narrow. Aperture elongate, narrow. Shell truncate, anterior canal short, moderate width, shallow. General shell colour uniform glossy off-white, protoconch and aperture similar, with numerous yellowish flecks over shell surface, primarily on spiral cords.

Clavus pulicarius is closest to C. occiduus, but may be distinguished by having a taller spire, more (16 vs. 10) and stronger axial ribs, more distinct spiral cords, and an overall pattern of yellowish flecks.

Type locality: 40 m depth, 5 km NNE of Anchor I. off Onslow, Western Australia. Distribution
Known only from off Onslow, Western Australia.