Meleys, called the Red Queen, was the dragon of the House of Targaryen. She was the dragon of Rhaenys Targaryen and the second dragon to die during the Dance of the Dragons.
Description
The Meleys ridden by Rhaenys Targaryen has scarlet scales and a crown of bright copper horns. In her youth she was said to be faster than both Karaxes and Vhagar
Rod the Dragon: Season 1
Rhaenys rides Meleys towards King's Landing. Her son Laenor Velaryon, who is to marry Princess Rhaenyra Targaryen, rides by her side on the dragon Sea Smoke
Meleys remains on the High Tide along with several other dragons during the funeral of Laen Velaryon
During the coronation of Aegon II. Targaryen, Meleys is chained in the Dragon Pit. She is eventually freed by Rhaenys and rides her out of the Dragon's Den, in her escape to the Dragonstone she inadvertently kills several minor humans
After the coronation of Queen Rhaenyra Targaryen, the Rhaenys and Meleys begin to patrol Rivendell and reinforce the blockade of the shipping lanes to King's Landing by Lord Corlys Velaryon
Rod of the Dragon: 2. season
Meleys and Rhaenys return to Dragonstone shortly before they learn of the death of Lucerys Velaryon
Rhaenys embraces Meleys as they prepare to depart Dragonstone for Rook's Rest, where they fight the Greenskins who are attacking the castle. Meleys repeatedly blasts the battlefield with his fiery breath, sending the Green forces into a panicked frenzy. Eventually Sunfyre and his rider Aegon enter the battlefield, in which a fierce aerial melee ensues. Meleys and Sunfyre brutally bite and claw each other, with the larger red dragon having the upper hand. After Sunfyre briefly escapes the stalemate, Meleys attacks the smaller golden dragon again and clamps his jaws around Sunfyre's right wing, which in turn bites and breaks off one of Meleys' horns. At the same time, Vhagar and Aemond arrive on the battlefield, and the young prince commands his dragon to hit Meleys and Sunfyre with a stream of fire. When Sunfyre bursts into flames and collapses with Aegon into the forest below, Meleys engages in close combat with Vhagara, in which the larger dragon's belly is slashed open with his claws as they shower each other with flames and dig their claws into each other. Both dragons crash to the ground and Meleys quickly recovers and manages to return to the sky as Vhagar hits the ground, only to be ambushed by Vhagar, hiding behind Raven's Rest and clamping her jaws tightly around the red dragon's neck. Meleys and Rhaenys share one last glance together as Vhagar crushes Meleys' neck in his jaws. causing her body to fall and in a fiery explosion, she crashes against the walls of Raven's Rest. This subsequently allows the Greenskins to take advantage of the newly created rift and invade Raven's Rest.
In the Books
In the prequel novels, Meleys was known as the "Red Queen", which seems to imply that she was the mother of several other dragons (much like Rhaenys was the grandmother of the youngest generation of dragonriders). Her exact age and lineage has not yet been determined. Before she joined with Princess Rhaenys, she was originally ridden by Alyssa Targaryen, daughter of King Jahaerys. When Alyssa claimed the dragon, the dragon guardians recommended Meleys as her mount instead of Balerion the Black Scarecrow, which she had considered but which was already old and slow. Alyssa was the mother of Viserys I and Daemon Targaryen. Likewise, Alyssa took both of her sons on horseback to Meley a few days after their births.
It seems that Meleys was indeed one of the oldest and largest dragons after Vhagar herself, and was probably one of the second-generation dragons that hatched to the original three of the conqueror generation (Balerion, Meraxes, and Vhagar). Vhagar was 181 years old during the Dance, and at that time she was said to be as big as Balerion during Aegon's conquest. Vhagar is also described as being five times the size of the young dragon Arrax, who was only about ten years old and just big enough to go to war.
Source: Fandom - The Dragonborn.
