Oscar, too, was almost transfixed.
Then slowly, but surely, the huge serpent moved closer to the two, intending to embrace the pair as one and crush them.
But the movement broke the spell so far as Oscar was concerned, and hardly knowing what he was doing the young captain hurled the dynamite shell at the water reptile.
It struck the serpent on the head, and with a strange hiss the monster set its teeth into the shell.
Oscar was pulling Andy with him.
There was a dull explosion, and the water was filled with bits of the serpent's head and neck and also with the sand which was stirred up.
When Oscar got up again he found the serpent's harmless body whipping itself furiously against the rocks.
Andy was so weak he could hardly stand, and Oscar had to support him back to the submarine craft.
All on board shivered when they heard of the sea serpent, and by turning the searchlight in that direction they saw the body still coiling and uncoiling on the sand.
"I wouldn't go out there for a million dollars," said Marney, the air man.