You can try this weapon as a Cow Mangler mod here:
http://tf2.gamebanana.com/skins/141421

Pootato's animation fix (Note, this will break animations for other Rocket Launchers)
https://gamebanana.com/skins/170311

"Mine eyes can but weep as they bear witness to the majesty... the BFG-9000!"

Since the release of Doom in '93, the BFG-9000 has been one of the most iconic and deadly weapons in gaming history. It's capable of launching giant balls of superheated plasma that shoot rays of death all around it.

A lot of work and care went into making this gun faithful to the original from Doom, from the model and it's centered viewmodel animations, to it's sound and particle effects. Everything looks and sounds like it used to in Doom, but updated for Team Fortress 2.

Credits:

ZombiePlasticClock: Model, compile, Kill Icon, Backpack icon
Dr. Pyspy: Textures, animation bugfixes
Paysus: Custom animations
Fissionmetroid101: Particle effects
Stachekip: Sound effects

Special thanks to Bloodfart for the awesome SFM Render and thumbnail!