
1) Colorful gastropod 2) Crawling marine mollusk 3) Nudibranch 4) Nudibranch, by another name 5) Snail without a shell
Found on
https://www.crosswordclues.com/clue/seaslug

Seaslug was a British naval surface-to-air-missile installed on warships during the late 1950's. Seaslug had a range of 58 km and was armed with a 135 kg high-explosive warhead. Seaslug was radar controlled and completely automatic, the control system detecting an aircraft, tracking it and when it was within range launch and guide the missile to th...
Found on
http://www.probertencyclopaedia.com/browse/RS.HTM
No exact match found.