Cliona:

Genus mostly endolithic, with surface papillae; some stages encrust substrate. Boring throughout life cycle.

Cliona lampa

Encrusting and boring large (to several square meters) areas of substrate, brilliant red. Less common yellow variety with same habitat and distribution. Kills corals and clam substrates.

Very common at shallow locations with strong water currents, inshore waters. 0.5-1 m.