Watch List notes:

EUBOIA. Eretria. Circa 500-465 BC. Hemiobol (Silver, 6 mm, 0.28 g, 6 h). Bull's head facing; on the nose, Ε. Rev. Octopus with body above and eight arms; all within an incuse square. BCD Euboia 336 (this coin). Traité II, 1, 1082 and pl. XXXII, 12 (same dies). Extremely rare. With an attractive dark patina as found. Uncleaned as found with some deposits. About extremely fine.
From the "Collection sans Pareille" of Ancient Greek Fractions and from the BCD Collection, Lanz 111, 2 November 2012, 336.