Myths about mermaids and sea creatures may be as ancient as they come, but modern filmmakers are still being beckoned by fantasies in the watery depths. It's not just Disney and Pixar's enchanting coming-of-age tale " Luca," either. Two international gems playing this summer, Germany's " Undine " and Saudi Arabia's " Scales," have also found fresh inspiration under the sea. 

Though the two share a common thread, they're also quite different. "Undine," currently streaming on demand, follows the romantic trials of a water nymph living and working in Berlin as a city historian. "Scales," in limited release Friday, is about a spirited young girl, Hayat, whose father refuses to sacrifice her to the sea, as is the tradition in their poor fishing village. 

For "Undine" writer-director Christian Petzold, the inspiration was born out of a desire to keep working with Paula Beer and Franz Rogowski. Near the end of their time shooting "Transit," he lied and said he had another script for them, vaguely referencing the story of a water nymph who takes on a human form when she falls in love with a man.

"They said to me, 'We would like it, but you have to write it first,'" Petzold said. "And so I was under pressure. But the pressure is very good for people like me."

Although Beer wasn't overly familiar with the origins of the myth, she knew the story generally: It's been the basis for ballets, poems, literature and even "The Little Mermaid." And besides, Petzold was going to put his own spin on it. 

"I really love that Cristian combined the myth and the modern world, so it's not a fairy tale movie with gowns and riding on horses and big wigs. It's got a more natural layer. But it's also a universe where it's OK to say, 'If you don't love me, I'll kill you,'" Beer said. "It was fun to play. She's not human, but she wants to be human. And she has a really pure heart. I think that makes her able to feel emotions that humans are scared of."

It ended up being an inspired choice for this pair in more ways than one. Rogowski discovered during their preparation that a lifelong issue with his ear drums that had prevented him from going underwater wasn't there anymore. Rogowski's underwater euphoria during his diving lessons left a major impression on Petzold, who was eager to recapture the feeling on screen.

"Scales" writer-director Shahad Ameen was similarly surprised that she ended up making a "mermaid film." 

"I never thought of myself as the writer who will do a film about mermaids. It never crossed my brain," Ameen said. "But I loved fantasy growing up."

After graduating from college and making a couple of short films she decided to indulge in a little magical realism in her work. After all, she was a poet, too, and was drawn to symbolism in Russian cinema. And then a striking image came to her: A mermaid being chopped in half in front of little girls by someone who looks just like the mermaid. She started writing immediately. 

"I knew I had gold with the idea of symbolizing Arab women and fear of women with those mermaids," she said. "It's the story of Hayat rejecting the body that she was given. And she doesn't understand its power and she actually kills it. And then slowly she starts understanding what her body means. Slowly she starts unlearning what the society had taught her about her body. And when she finally accepts herself the world accepts her."

Ameen's stylish black-and-white film has already had a successful festival run, everywhere from Venice to SXSW and was actually Saudi Arabia's Oscar submission this past year. She's hopeful U.S. audiences will respond to it as well. One of her best screenings, she said, was at William & Mary in Virginia. 

"I hope that people will enjoy seeing something different," Ameen said.