Haddon's Anemone

S. haddoni is characterized by a folded oral disc that reaches 50–80 cm (20–31 in) in diameter with a 1–2 cm (0.4–0.8 in) tentacle-free oral area. The tentacles have a rounded tip and the end may be green, yellow, gray, or rarely, blue and pink. The column, visible when the animal is closed, has small, non-adhesive bumps (verrucae) which are usually the same color as the column and not visible. The tentacles are yellowish or tan. At the circumference it has alternating short and long tentacles.

S. haddoni is found on sandy substrates and is widely distributed throughout the tropical and subtropical waters of the Indo-Pacific region, from Mauritius to Fiji and from the Ryukyu Islands of southern Japan to Australia.

In Thailand, S. haddoni is called Hed lub (เห็ดหลุบ, "bob up and down mushroom") what with its appearance, which resembles a mushroom that pops up and down. On some islands, such as Ko Samui or Ko Pha-ngan, these sea anemones are used as an ingredient in a local seasonal dish called Kaeng kua (แกงคั่ว), even though they are protected animals in Thailand.