Megatron

Comical, yet ruthless, Megatron is the evil leader of the Decepticon armada with a secretly soft heart. Somewhat of a reflection of his greatest adversary, Optimus Prime, Megatron seeks to control the world at any cost necessary, even allying himself with other baddies, such as Cobra Commander.

Equipment

 * Fusion cannon: Megatron has his own gun known as the Fusion cannon. He toted it while with Nightmare Moon, but hasn't shot it at any ponies.
 * Matrix of Leadership: Megatron once had ownership of the Matrix of Leadership and planned to use it to take over the world, until he was thwarted by twilight Sparkle, Rarity and Pinkie Pie.

Behind the scenes
Megatron is one of the two main characters of The Transformers series. Since The Transformers and My Little Pony are both owned by Hasbro, and since both have comics published by IDW Publishing, crossovers between the series have not been to uncommon. Megatron was sent to a dimension with Lyra Heartstrings, Twilight Sparkle and Moon Dancer during the events of The Transformers vs G.I. Joe, three unicorns when he desired to find Unicron. The multiverse is as cruel as is vast.

Voice actors
Many of Megatron's voice actors have appeared in My Little Pony works, such as:

English:
 * Frank Welker: Various productions -- also portrayed him in crossover promotions.
 * Garry Chalk: Beast Wars
 * David Kaye: TransTech
 * Peter Cullen: BotCon

Japanese:
 * Wataru Takagi: Beast Wars
 * Shigeru Chiba: War for Cybertron

French:
 * Robert Dubois: Prime

Italian:
 * Dario Oppido: War for Cybertron
 * Raffaele Farina: Animated
 * Oliviero Corbetta: War for Cybertron (game)

German:
 * Peter Sura: War for Cybertron

Polish:
 * Paweł Szczesny: Prime

Portuguese:
 * Guilherme Lopes: War for Cybertron, Prime
 * Nestor Chiesse: G1 Cartoon
 * Antônio Moreno: Prime
 * Affonso Amajones: Animated

Appearances

 * Are You Ready For The Summer?
 * The Transformers vs G.I. Joe
 * "When Worlds Collide"