This is a Venus flytrap sea anemone (Actinoscyphia sp.) from the Gulf of Mexico. Its common name includes references to two terrestrial plants (“Venus flytrap” and “anemone”), but the species is classified as a type of polyp. It closes its tentacles to capture prey or protect itself.
one of my favorite creatures - the nudibranch. Essentially a shell-less snail, so they're salt water 'slugs' but in the most flamboyant color combos and shapes imaginable. If Lacroix had a say in biology he would have certainly done this group.