On your usual walk along the beach, you hear what sounds like a distressed dolphin that may have beached itself and can't get back in the water

You follow the noise to it's source to find a very large octopus Mer, it's body being a stark black with various shades of purple for fins. It's tendrils having a dark blue underside

The creature chirps and trills in distress, trying to get back in the water. How the hell are you going to get this behemoth of a creature back in the water?