During a dive a shell (21 x 14 cm) of the tropical sea snail Melo broderipii (Gray in Griffith & Pidgeon, 1833) was found on the bottom of an artificial lake at Hoofddorp. Attached to the shell were some living Dreissena polymorpha Pallas, 1771) and Valvata piscinalis O.F. Müller, 1774. Maybe another diver has placed the shell here as a joke?