No, it's not just a gun that tumbles people, I'm thinking of this.
Who uses bullets! Men use themselves!
So basically it launches the player foward while tumbled at idk, 45-75 velocity? So vehicle damage from tumble will kill people or highly damage them, and it might even bounce around to hurt some other players.
Weapon module could be no module, or default gun recolored pale green.
The fire sound could be rocket launcher fire sound.
Maybe if you're a nice person, you could make a custom module.