The coastline

It was a regular sunny day at the beach. The hot sun overhead, the sea breeze flowing by, and beach goers were enjoying some peace and relaxation. All was good until it came, it flowed in with the current as it hid in plain sight. It could see the people coming into the water to swim surf and play, the people that just casually sit on the sand and the families that played everywhere. The question was, what would it decide to do?