It would be nice so see it from the top looking down. I'm thinking from the little things sticking up from its body that it maybe a Cowrie, through the foot is a little long for one. Does it have a shell? If not I think it's probably some type of sea slug.
yes, it has a shell. others have mentioned cowrie, but i don't think it's shell is shaped like one. i thought the foot was long also. it looks more like a giant stomatella than a cowrie IMO.
i'll try to catch a pic from the top tonight.
you guys are right. under further scrutiny (seeing it from the other side) it is a cowrie. it came out of a friends' tank i bought as he got out of the hobby. he had a few of them, and now i have a few of them. the "hairs" only come out at night.