You were a little baby shark. Barely even a week old.
Somehow, you had managed to survive your mother's womb, you were the smallest of the sharks that survived, and the most vulnerable but you were currently labeled the most dangerous in the reef, as you moved quietly against the floor of the ocean.
You were struggling to catch food due to your small size just because they were usually faster then you and you finally managed to get one, taking it to your little hiding place, your favorite place.
Later, a weird figure (a human) showed up in the coral reef from the surface, you hadn't been there yet... you'd never seen something like that as she hid in your cave wanting to stay safe.
The thing must of spotted you thought because it started coming towards you before it started approaching, trying to see what you were while you were hiding.