Is it a whale? Is it a dolphin? 1-of-a-kind hybrid fascinates scientists

Let's face it: Unlikely couples hold a special place in our hearts, whether Romeo and Juliet, Edward and Bella -- or a melon-headed whale and a rough-toothed dolphin that apparently enjoyed an unlikely inter-species romance a few years ago in the waters off Hawaii.

Fast forward to last year, when a team of scientists with the Cascadia Research Collective on an expedition near the island of Kauai spotted a strange creature -- not quite a melon-headed whale, not fully a rough-toothed dolphin.

"It's the first record of a hybrid in the wild involving either of these species," Robin Baird, a research biologist with the Cascadia Research Collective, told ABC News.

The new creature looked like both species, but with a few things awry.

It didn't, for example, have the rounded head of melon-headed whales, and yet its beak was shorter than those of rough-toothed dolphins. Below the leading edge of the dorsal fin, the patterns on it were like those of melon-headed whales, but at the base of and immediately below the dorsal fin, it had darker-colored blotches, similar to those found on rough-toothed dolphins.

The organization wrote in a paper on Friday that after a biopsy of a sample collected from the creature in August 2017, suspicions were confirmed: The offspring of two species never before been known to mate, despite occasionally swimming in mixed groups, well, had.

Baird said this is unlikely to be the start of a whole new species of dolphin, however, because male hybrids are often sterile, and because only one of its kind has been spotted so far.

Despite the name, melon-headed whales aren't actually whales -- they're part of the dolphin family, and they tend to swim in large pods with hundreds of others of their kind. Rough-toothed dolphins, on the other hand, prefer to stay in ones or twos.

Baird told ABC News the hybrid animal was pictured with a single melon-headed whale both times they spotted it, which added to the mystery surrounding the unusual animal.

"What could have happened is that the mother, a melon-headed whale may, have become separated from her pod, begun to stay with single rough-toothed dolphins, and become used to swimming with the other species," Baird said.

His team is heading out to Kauai soon for another field project and hoping to discover a little more about the origins of this mysterious creature.

"If we were lucky enough to find the pair again, we would try to get a biopsy sample of the accompanying melon-headed whale, to see whether it might be the mother of the hybrid, as well as get underwater images of the hybrid to better assess morphological differences from the parent species," he said.