The Night howler dart gun, also known as the sniper serum gun, is a unique weapon owned by sheep chemist and sniper Doug Ramses, who used it to shoot predator mammals with paintball-like pellets containing a highly potent, lab-synthesized Night howler serum, turning them "savage".
This weapon is very similar to a real-life air powered tranquilizer gun. It has a patterned black and yellow mark on either side and a gun chamber located at the rear that can be loaded with three pellets at once. The gun is capable of shooting animals from a great distance, evidenced by Doug sniping the small Emmitt Otterton through the open window of a moving car while hiding behind a far away boulder, as well as shooting Renato Manchas through an open window from a considerable distance.
Despite its sniper capabilities, the gun is rather small; it looks like a pistol in Doug's hands. The barrel and targeting scope can be detached so as to be put in a briefcase-like gun case for transport.
Role in the Film
The gun is used by Doug to turn Emmitt Otterton and Renato Manchas savage, along with thirteen other predators, leading them to be secretly quarantined by Mayor Lionheart. After the missing mammals are found, Doug continues to use the gun on many other predators, most notably a polar bear in Tundratown, leading to an attack that leaves a caribou critically injured.
When Judy Hopps and Nick Wilde infiltrate Doug's lab, they find a case containing the gun and try to take it to the Zootopia Police Department. Before they can do so, they run into Assistant Mayor Bellwether, who is waiting for them at the Natural History Museum.
Realizing that Bellwether is the true mastermind behind the anti-predator agenda, they try to run away and get the gun case to the ZPD, but they are knocked into a pit-like, aerial-view exhibit by one of Bellwether's henchrams, making them drop the case. Bellwether then removes the gun from the case and uses it to shoot Nick Wilde in the neck, who appears to turn savage.
However, unbeknownst to Bellwether, Nick had secretly replaced the serum pellets in the gun with blueberries before she could get ahold of it, rendering the shot ineffective. Meanwhile, Judy records the rogue mayor's crazed speech with her carrot pen.
It is unknown what happened to the gun after Bellwether was arrested.