A massive attack of caprellids is reported here, that is related to a local mortality event of gorgonians in North Sulawesi. Three species of sea fans were affected by the presence of Metaprotella sandalensis, a caprellid widely distributed in the Indo-Pacific. The degree of damage here documented was in relation to the skeletal features of the gorgonian species. The amphipod gut contents were analysed, highlighting an unusual trophic source for caprellids and a new predator for gorgonians. This phenomenon is discussed also evidencing parallels between colonial marine invertebrates and their predators and terrestrial plant–herbivore interactions.