Hercules club mud whelks are common large marine snails on Australia’s eastern coast. True to their name, they are foundational heroes of the oyster reef, yet with their strength comes the ultimate sacrifice. Oyster larvae settle on the whelks, and some whelks carry up to four large oysters on their shell. As the oysters grow larger, the whelks slow and sink into the mud. Thus Hercules whelks appear to play a unique facilitative role for oysters as ecosystem engineers in sediment-dominated estuarine environments.