Megatron

Megatron is a fictional character from Transformers.

Transformers Generation 1
Megatron is a gun. His enemy is Optimus Prime. They are brothers. On Transformers: The Movie,Megatron turns to Galvatron.

Transformers Beast Wars
Megatron is the T-Rex. His enemy,Optimus Primal,wants the Maximals to have victory.

Beast Machines
Megatron was a red dragon in Beast Machines. Also he appears on episode 2 talking to Optimus Primal.

Transformers: Titanium
Megatron was on Transformers: Titanium. Go to the category "toys", and go to Titanium series and you will see the Titanium Megatron toy.

Transformers Robots In Disguise
Megatron was a Predacon then a Decepticon. He has lots of modes, but his first one is a robotic dragon. Later he turned to Galvatron.

Unicron Trilogy
Megatron was a tank on Armada. He didn't turn to Galvatron. On Energon Megatron is a jetplane and turns to Galvatron. On Cybertron he is a gigantic car and jet and he turns to Galvatron too.

Transformers: Warriors
Megatron was a white gun and turns to Galvatron on comic #56. Galvatron was upset why he was defeated and tried to knock out as many Autobots as he can. There was a prototype Megatron toy, but it was never released. On the Transformers: Universe Warriors series there was a Legends Class Megatron toy that was never released until 2009. Megatron's (and Galvatron's) enemy, Optimus Prime, has tried to take the cannon off of Megatron's (and Galvatron's) arm like in the first series.

Transformers: Universe
All the series that Megatron is on (except the movie) are toys of him.

Transformers 2007
Megatron was a jet on this series. He was captured by the Air Force, gets defeated, and gets under the ocean.

Revenge of the Fallen
Megatron returns and becomes a tank on this series. He gets defeated by Jetpower Optimus Prime.

Transformers: Animated
Megatron is a jet and never turned to Galvatron.