[Xenophora are] a gastropod that cements other mollusc shells, small stones, dead coral or any other miscellaneous handy debris to the outside of its shell as it grows.

It is thought that shallow water Xenophora attach these items to themselves for visual camouflage, but they also use these extra adornments for increased shell strength and to act as stilts.

Images via flickr from zymoglyph and Judith Hoffman.
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