It appears to be a millipede with a camouflage case of bits of vegetation, rather like the husk of a sweet chestnut. The case is about 2 cm long. I found the creature on a beach in Liguria, Italy, but suspect that it may have fallen or been blown down from vegetation higher up. The millipede has a black exoskeleton, and has a black and white "scary" face. When alarmed, it very rapidly retreats right inside the case and the opening closes.
Message was edited by: Jackie
It is a case-bearing moth larva, of which there are many species.
The wariness, and rapidity of retreat into the case is typical. I have been frustrated trying to photograph them because of difficulty getting close while they are extended from their case.
Here's just one example: Luffia ferchaultella
The particular species in your (good) photo, I can't say.
FYI, there are also bagworms, which are also moth larvae, which have a similar lifestyle
Thank you very much, Mike. One of the fishermen said it was common, but didn't know the name. Actually one of the pictures to the right of the bagworm article looks exactly like the insect I found. I managed to get some videos of it as well, e.g. https://dl.dropboxusercontent.com/u/2782469/MVI_0907.MOV. It seemed oblivious of me unless I touched it.
Thanks for the video.
Unfortunately, it is rather large (604Mb) so it may not be seen by many folks as it takes too long to downoad (over 45minutes in my case). If you have a smaller version, that would be useful.
Link to short video (18 seconds; 11 MB): https://dl.dropboxusercontent.com/u/2782469/Bagworm2.mp4