A realistic 3D model of a shark, featuring a streamlined, torpedo-shaped body with a pointed snout and crescent-shaped tail. The skin should have a rough, sandpaper-like texture, with detailed scales and subtle color variations ranging from dark grey on the back to a lighter shade on the belly. Include distinct features like the dorsal fin, pectoral fins, and gill slits, with a slightly open mouth revealing rows of sharp, triangular teeth. The eyes should be small, black, and lifeless, adding to the predatory look. The model should convey a sense of movement, as if gliding through water.