1) Huge ray 2) Manta ray 3) Manta ray, by another name 4) Octopus 5) Underwater menace
Found on
https://www.crosswordclues.com/clue/seadevil
USS Seadevil was an American submarine of 1525 tons displacement launched in 1944 which saw action during the Second World War. USS Seadevil was powered by diesel engines providing a top speed of 21 knots and was armed with one 4-inch gun, two 20 mm Oerlikon anti-aircraft guns; six 21 inch bow torpedo tubes and four 21 inch stern torpedo tubes.
Found on
http://www.probertencyclopaedia.com/browse/RS.HTM
No exact match found.
