Yanmega is a large, dark green dragonfly Pokémon. Its large eyes are red with black lines that make a sideways "T" shape in each one. It has two large, white fangs or mandibles next to its small mouth. Its immense jaw power allows it to bite apart foes while flying by at high speed. Each of Yanmega's segments have a red spot on them, while the last tail segment has a black triangular plate. It has two similar plates on the back of its thorax and a third on its head. It has four white, oval wings with red tips, and there are two smaller white wings on the end of its tail. Yanmega can create shock waves by beating its wings. These shock waves are so powerful, they may inflict critical injuries on the foe. These wings are powerful enough to carry an adult human. Yanmega also has six thin, black legs.
Jessie has a female Yanmega that debuted in The Thief That Keeps on Thieving!, which also served as the species' main series debut. After catching her as a Yanma, Jessie used her in a battle against Ash and his friends, where she evolved into Yanmega in the same episode. Yanmega was then used in several Pokémon Contests before Jessie left her at the Team Rocket HQ when she headed to Unova, so she would not attract attention by using a Pokémon foreign to the region.
Despite having significantly higher Special Attack than Attack, Yanmega gives out 2 Attack effort values when defeated.
Two generations after Yanmega's debut, Mega Pokémon were introduced. These Pokémon have the word "mega" in front of their names, similar to Yanmega's name in Japan.
Origin
It is, as its name suggests, based on the Meganeura monyi, a particularly large, prehistoric species of dragonflies. Its species name suggests it's based on a green darner.
Name origin
Yanmega and Megayanma are a combination of 蜻蜓 yanma (large dragonfly) and Meganeura (a genus of gigantic prehistoric dragonflies). Megayanma may also literally be "mega yanma".