The thing is...I saw this before I watched Sherlock and I didn't think it was funny. Now I've come across it again after I've seen all of Sherlock and I am dying right now, that's totally what happened.
You can take this the Disney way, or the nerdy way! Obviously Ariel is Amy Pond and Prince Eric is Rory and they had a baby named melody! It all makes sense now! I... I.... I.... Just died a lot I think.