what is this thing?!?!?! It moves real fast and can get into real small spaces. my camera sucks at closeups but i found this on google. also there is a small snail that moves pretty quick and he is all over my live rock is that ok? he is brown and his shell is mussel shaped. he is only the...

I found this weird creature in my 72 gallon. Does anybody know what it is? Very creepy... http://i591.photobucket.com/albums/ss357/tstockda/creepy2.jpg http://i591.photobucket.com/albums/ss357/tstockda/creepy.jpg