Going swimming?

Beware of the Weever fish!

Beware of a little sandy coloured fish that lives in the English Channel. It spends most of the time actually buried under the sea bed with just its venomous dorsal fin showing above the sandy bottom. On the rare occasions when it is plentiful, rows of erect black triangles decorate the sandy floor of the sea bed;

Woe betide a bather who steps upon a buried fish. The pain is usually described as excruciating as the spines embed into the human flesh and discharge their venom. The pain is at its most intense for the first two hours when the foot goes red and swells up and is then it feels numb until the following day with irritation and pain that may last for up to two weeks. Sometimes, the spine breaks off in the foot and it will cause discomfort until it is removed.

http://www.glaucus.org.uk/weever2.htm