The body is black and there is a yellow spot and the end of it in the "tail" area. It is almost positively a type of slug. It has two sensing antennae (I can't remember their name, or do they have a name?) on the top of it's head, as a lot of slugs do, that protrude outward from the front of the " head" area.
I found this slug in Norway on a hike in the one of 7 mountains (one of the hikes from the funicular) surrounding Bergen. The habitat I found it in was a pine forest with lots of rocks, and lakes not too far away. The climate there was cool and wet with frequent rain.
There is a tan kind of crevice or hole in the side of the slugs body that opens and closes. It is visible in the first photo. I'm not quite sure what it is. I don't think it's a mouth because Gastropods have stomach feet.