Book, you unlocked some of the snail. If you want to unlock all of it, then you need to find and eat more of them. No one has really hunted down stuff they didn't fully unlock, so I thought I'd point it out.
@Nathair: Another organic thing. This one was flat and very thin, but was much wider than the slime- it couldn't even stretch itself far enough to feel both ends at the same time. There was a thick line in the middle of it, that split off into smaller lines, then even smaller ones. Whatever this thing was, it felt somewhat soft. A couple small moving things were on the thing. Whether they had a direction or not, the slime couldn't tell.