So my theory — I think mermaids have the ability to travel to other worlds without the need of a portal…
We’ve touched on that before. I think this might be a possibility. I wouldn’t be shocked. Not only did Emma and Snow come back through the well, but Rumple brought magic back by the well and the following sprung to mind:
August: Water is a very powerful thing. Cultures as old as time have worshipped it. It flows throughout all lands, connecting the entire world. If anything had mystical properties – if anything had magic – well, I’d say it’d be water.
–1 x 13 “What Happened to Frederick”
The flowing throughout all lands and connecting the entire world is something they just might return to.
Keeper of Rumplestiltskin's and Neal's spears and war paint and crystal ball.