Snail with epizootic moss growth
An epizoon is a parasitic or commensal growth of one organism on another. This occurs frequently within aquatic environments (like anemones on crabs), but is less common on land). I haven't found another such case for terrestrial snails in the literature so far. Here it appears to help camouflage the snail. Photographed in Udzungwa national park, Tanzania. Paul Bertner 2014.