You will need two contrasting yarn collors, stuffing, and something to use for eyes. (Safety eyes, googly eyes, embroidery)

The samples were made with a 5 mm. hook. I have a bit of a tight stitch, so using a 4 mm or 3.75 mm hook may yield better results for some.

I found that Caron Simply Soft yarn (used on the pink one) had a little more give and gave a better illusion of a sea creature.