Loudener- opposite of a silencer. Increases damage, but creates a huge flash with a loud bang giving player position away (also increases recoil)

What about a shistol? A shield attached on a pistol, with the gun barrel going through the shield.

The ex-wife.

I can just imagine a haggard woman with her hair in curlers clinging to the back of the player nagging them with directions and belittling their performance (in the game ). The benefit to having her strapped to the player would be taking damage from the player getting shot in the back and like one side of their head. Maybe to balance it even more would be to also slow the player down a little for carrying the extra weight. Oh and if there is a point/money/experience system attached to the game, she could take half!

Some other (D&D inspired) ideas I've had are:

Magic Mirror - The player looks to be a shifting image that is constantly blurring and cutting in and out. Kinda would look like they're lagging though lol. Could have an alt fire to place a image of the player, similar to other "hologram" systems in other games.
Bullet Rubber-izer - Adds a magic, rubber coating to the bullets that makes the bullets ricochet around briefly before disappearing.
Velocity Reduction Muzzle - Slows the bullet down to a crawl as it moves through the level, but it doesn't decrease it's lethal potential. An enemy could run into it and take the full or more damage from just that one bullet.
Vorpal Muzzle - Reduces the damage of the projectile significantly unless it's a crit/head shot, in which its an instant kill/gib. Would be fun for advanced players and snipers.
Bullet Blinders - Similar to blinders on horses, these will narrow the spread of rapid fire weapons, but your turn speed is slowed down when firing.
Ammo Mag/Clip of Holding - Significantly increase the amount of ammo in a mag/clip meaning less reloads! Could be balanced by having to refill it/them before reload, so the player would still collect the same amount of ammo on the level, but it might take longer.