What is the magic horse in Frozen 2? The trailer for the Disney sequel expands the Arendelle lore massively, leaving behind a lot of mysteries ahead of its November release. And, perhaps the biggest is an ice horse that has a mysterious connection to Ice Queen Elsa.

The full teaser did, showing Elsa learning to use her ice powers to run on the sea, only to be knocked back by waves. However, the new footage continues the scene: underwater, Elsa attempts to swim to the surface but is confronted by a blue-eyed horse seemingly made out of water. It leaps forward in flashes of lightning, confronts the Queen, before disappearing into a field of bubbles. Later in the trailer, Elsa is shown watching an ice-made image of presumably the same horse leaping about before disappearing and replaced by the outline of giants.

Related: Frozen 2: Everything You Need To Know About The Disney Sequel

The new Frozen 2 synopsis states that "Elsa encounters a Nokk - a mythical water spirit that takes the form of a horse - who uses the power of the ocean to guard the secrets of the forest." Nokk originates in Germanic legends and is known by various other names: Bäckahästen (the "brook horse") in southern Scandinavia; and Ceffyl Dŵr (the "water horse") in Welsh. It would seem that, fitting of Disney's history with adapting fairy tales, their take is a twist on the assorted legends; traditionally, Neck (as it is also known) operates as more of a siren, luring men to the death rather than saving them as shown in the Frozen 2 trailer.

Elsa and the Horse in Frozen 2

While there's very little information on the role Nokk has in Frozen 2's plot, the suggestion in the trailer is that it's leading Elsa on the next step of her quest: the second vision appearance hints that it's leading her to the giants and then a mysterious portal beyond. That would suggest the equine form is something of a guide or progenitor for the characters on their new plot.

One of Nokk's defining traits is its ability to shapeshift, suggesting that there's a powerful being behind it also. As we know that Frozen 2 will be dealing with other gifted people - the teaser had one new character manipulating air - this could be the sign of a water-controlling person out there.

The new Frozen 2 trailer may actually provide more resolute clues. Clearly, the movie will delve into how exactly Elsa got her ice powers (something already teased recently by an international poster), with Pabbie the rock troll saying "the past is not what it seems". This suggests that, far from the lifelong affliction as presented in the first film, Frozen 2 will reveal Elsa's powers are a more literal curse. One shot in the trailer shows Elsa as a child sat in bed, while the next appears to show her mother at the window, looking up at aurora borealis. Could the northern lights, with their generations of mystical meaning, be the root cause?

Frozen 2 Elsas Mother

If so, that would connect the origin Tarzan); could Nokk the water horse be some embodiment of Elsa's mother, watching over her daughter years later?

Related: Frozen Theory: Where Did Elsa's Powers Come From?

Nokk the water spirit will be one of Frozen 2's biggest mysteries as the release approaches at what sometimes feels like a glacial pace. But it's far from the only surprise in store. Find out more in our Frozen 2 trailer breakdown.

Next: Every Animated Disney Movie