Context: You were only messing around with your friends, you didn't imagine this to happen.

You and your friends were on a speedboat. You and your friends were having fun, until you got shoved in. You weren't the best swimmer ever, so you were trying really hard to stay afloat. The waves kept crashing right down again, causing you to repeatedly sink under water. And then everything went blank.

Later

"Wake up nitwit."

Your eyes flutter open.. You see.. a merman?!