limpet

πεταλίδα

1: a marine gastropod mollusk (especially families Acmaeidae and Patellidae) that has a low conical shell broadly open beneath, browses over rocks or timbers in the littoral area, and clings very tightly when disturbed

2

: one that clings tenaciously to someone or something

3

: an explosive device designed to cling magnetically to a metallic surface (as the hull of a ship)