Of a sudden the moss was uplifted like a blanket and the young diver fell back in amazement.
Before him stood a monster as startling as it was horrible.
Whether it was fish, beast, or demon, he could not tell, but it was certainly so awful that his very heart appeared to stop beating as he gazed upon it.
It had a long, round body, fat and blubbery, with two legs in the center, two arms near the neck, and at the end the tail of a fish.
The head was shaped like a huge pear, with eyes blinking savagely from either side of a nose which was as long and pointed as a cow's horn.
The mouth of the demon was wide open, showing a double row of sharp, bluish teeth and a tongue covered with yellow slime.
All told, the creature was at least ten feet long, and when it stood up it towered well over the heads of the two divers.
On the instant Dave raised his gun, but his father was before him, and a bullet from Amos Fearless' submarine gun took the demon squarely in the breast.
Hardly had the bullet reached its mark than the demon uttered a roar which rang in the divers' ears like thunder.
As if by magic the roar was answered from half a dozen near-by places and the moss was flung right and left.