Fusion cannon

The Fusion cannon is the primary and iconic firearm used by Megatron, the leader of the Decepticon forces. Of course, he's really actually used the gun during his run ins with the ponies, but it looks cool.

I used to wonder what vengeance could be, until you all shared its magic with meeeee
Galactic Conquest!
Tons of fun!
A vast empire, beautiful and strong!
And tyranny makes it all complete, yeah!

Fiction

Friendship Through Tyranny

Megatron held the gun in one hand and held Nightmare Moon in the other, obviously ready to to some pretty sinister stuff.