Balls of bubble wrap washed up on the beach?
Each little bubble is an egg capsule produced by the common whelk. Whelks reproduce in the autumn. Several females often attach their eggs to the same egg mass, creating puffy balls of egg cases. The eggs hatch in the winter, the juvenile snails disperse, and the empty egg cases wash up onto the beach.
Whelks can live for up to 10 years.
Sailors used the empty egg cases as wash sponges.
Fascinating subject for a snapshot.