The USS Stein Monster was a creature that apparently attacked the Knox-class destroyer escort USS Stein. She was named after Marine Tony Stein, who received the Medal of Honor posthumously after his part in the Battle of Iwo Jima. In 1976, the ship was attacked by an unknown species of giant squid. The creature damaged the "NOFOUL" rubber coating of her AN/SQS-26 SONAR dome. Over 8 percent of the surface coating was damaged. Nearly all of the cuts contained remnants of the curved claws found on the rims of suction cups on some squid's tentacles. The claws were much larger than any reported at that time. The creature may have been up to 150 ft in length. However, this is only half the average for the proposed Tuethis rex.
As unbelievable as it sounds we know more of the Moon's surface than the bottom of our oceans. This however on its own does not prove the existence of undersea monsters such as the USS Stein Monster. It does however prove that since much of the ocean is unexplored, there could be cryptozoid animals lurking in the dark and vast underwater world. That we believe are extinct or that we have never discovered. The USS Stein monster could well be an elusive undersea reptile (dragon) or sea creation we have never laid eyes upon!