The Supernova Dragon was released on 2/24/2013 with the addition of the "Search" feature. It represents a fusion of all three Space Trio dragons. It is considered to be Ultra Rare due to the very uncommon occurence of receiving an egg from the action. You can only obtain a maximum of 3(citation needed).
This enormous egg pulsates with an intense fusion of burning energy.
Hatchling
With a shock and a bang, the egg bursts open! This newborn dragon is way bigger than the others and seems to harbor an intense energy inside of its body.
Mature Hatchling
This baby dragon is way bigger than the others and seems to harbor an intense energy inside of its body. It's getting stronger every day, has grown three sets of wings, and its tail has split into three!
Adult
In the beginning, there were only three. The three held the power to create something of great proportions. With their magic, a light was formed. The light contained a tremendous power. Within it, another being was formed. The light grew larger, and it engulfed the entirety of space. The new being was born. With the combined strength of the original three, it was unstoppable-- it was the strongest being to have ever been created. The three had seen what they had done, and they were terrified. With the last of their remaining magic, they fought the beast and sealed its magic away. The beast, exhausted of power, transformed and dissipated away into a large light. After using all of their power to stop the beast, the original three perished into light. This is the legacy left by them-- the Supernova Dragon.
The Supernova hatching sequence is special in that the symbols on the egg extend out to one another in the centre and crack from the middle. The egg also glows more as it cracks.