Liquification/Hydrophysiology/Water Mimicry: User is made up of or can transform their body completely into water or other liquid substance. Users' transformed forms can be either anatomically identical to their normal forms, aside from being made of water, in which case they contain all organs and are somewhat vulnerable to attacks, or users can transform into homogenous matter, without any part of their form being more important than the other.
Been rewatching Avatar and still have so much love for these characters. I enjoy thinking of Iroh meeting Zuko’s dragon, sometime after The Search. It would be a nice way of bringing the symbolism of the dragons in their story come full circle.