There are a small number of land Gastropods such as some snails, slugs, etc. There are two eyes on stalks peeking out from under the shell. The points on the shell protect it from other animals. This is a nudibranch, basically a snail without a shell. The tuft of yellow on the right side is the animal's gill cluster.
Nobody is sure why some nudibranchs are so brightly colored.
Magnetite is used for hardening the teeth of the radula in chitons, so they can scrape coraline algae off of rocks. These creatures are extremely slow moving. In a year, a chiton may not move more than ten feet. They can detect the presence of light with primitive eyes embedded in the shell plates. A chiton is stuck to a rock.