This snail is found in the Indo-West Pacific, from the east coast of Africa to Hawaii and Guam, and also the Red Sea.
Drupella cornus lives on corals, commonly Acropora spp. and other members of the family Acroporidae.
The snails are obligate coral feeders - they feed by rasping away the external coral tissue using the radula, then feeding on the inside of the polyp using the proboscis. They do not digest the nematocysts or zooxanthellae. They also do not ingest the calcium carbonate skeleton of the coral.
This snail is naturally common across its range but during population explosions can be extremely abundant - up to 175 individuals per square metre.