I was on a white sightseeing boat, where the benches run along the wall and look out to the water. There was no one on board but Jim and I.
I got up to look over the rail, and saw a large animal swimming toward me with purpose. I stepped back as it reached us, and an unnaturally large platypus climbed over the rail and went to sit on the bench.
A few moments later, a platypus mermaid popped her head over the rail, and tried to get him to come back. "Come back, Pudge! Come on!"
Then a chase around the deck ensued. I was surprised how fast the critter could run, and then I realized we were swimming.
Eventually, they swam through the archway and out the door.