Take a dip

You slide softly in the water with a small plop and swim near the middle. The water is deeper than it seems, you realize, as you float on your back in the cool, clear water.

Too late you feel something slimy winding itself around your ankles. Screaming, you struggle frantically, but the tentacle quickly tightens so you can't escape. A second one lashes out of the water and keeps your arms bound to your sides. Your bikini is ripped to shreds as you are being restrained, and it finally reveals itself.