The intangible threat would be the most deadly weapon!
As the Stingray dove for the bottom of the sea, it completely disappeared in front of everyone. The players could not even track its movements.
It was a mistake to believe that one could see anything at the bottom of the ocean—especially in the middle of the sea. In fact, due to the distraction caused by the reflection of the water's surface affecting their vision and the decreasing visibility beneath the water, the players' human eyes could only see the white item under the sea within a few dozen meters. Not to mention gray-colored stuff; the water quality was unfavorable, so they could only see around 10 meters deep under the water surface from the ship.
