noun
goose barnacle
A stalked barnacle of the genus Lepas, often found attached to driftwood or floating objects. The name comes from its resemblance to an eboshi (traditional Japanese hat).
海岸に流れ着いた流木に、たくさんの烏帽子貝が付いていた。
Many goose barnacles were attached to the driftwood that washed ashore.
烏帽子貝は、船底に付着して船足を遅くする
Goose barnacles can attach to ship bottoms and slow the vessel down.
フジツボ (acorn barnacle) is a sessile barnacle that attaches directly to rocks, while 烏帽子貝 is a stalked barnacle often found on floating objects.
From 烏帽子 (eboshi, a traditional black-lacquered hat) + 貝 (kai, shellfish), referring to the shape of the barnacle's shell.