Gastropod attacking mussel

Gastropod attacking mussel

Observation - Gastropod attacking mussel - UK and Ireland. Description: Sorry it's not a great photo. This gastropod was caught attacking a Mussel in a colony on a groyne on Portobello beach. Can anyone suggest even a Family?

Sorry it's not a great photo. This gastropod was caught attacking a Mussel in a colony on a groyne on Portobello beach. Can anyone suggest even a Family?