Natica arachnoidea, common name the spider moon snail, is a species of predatory sea snail, a marine gastropod mollusk in the family Naticidae, the moon snails.
The size of an adult shell varies between 13 mm and 26 mm.
This marine species is distributed in the Indian Ocean along the Mascarene Basin and Mozambique; the Andamans; in the Western Pacific Ocean and Australia.