|Sell Creep Price:||30|
|Deals extra damage to ghosts and spectres.
Originally brought to the Gungeon by a team of investigators who suspected that something strange was going on.
Proton Backpack is a gun that fires a slow, homing laser stream. It locks onto enemies once it hits.
- Electron Pack - If the player also has Zombie Bullets or Ghost Bullets, kills with the Proton Backpack spawn Gunslinger's Ashes ghosts that attack enemies.
- The lock-on feature makes the gun ideal for bosses and strong mobs.
- This gun is a reference to the anti-ghost weapon from the movie Ghostbusters.
- The tagline is a reference to the one of the movie's most famous phrases, "Don't cross the streams".
- The "something strange" mentioned in the Ammonomicon entry is a nod to the Ghostbusters theme song which asks, "When there's something strange in the neighborhood, who ya gonna call?"
- The "team of investigators" is presumed to have been the Ghostbusters themselves.
- The Electron Pack is most likely a reference to the Wunderwaffe DG-2 from the Call of Duty Franchise.
- The shape of the Proton Backpack in the Electron Pack Is similar to the shape of the Blood launcher from Nuclear throne
Proton Backpack's appearance with the Electron Pack synergy.