An Alien Stiletto (or gimlet weapon) is a device designed to kill aliens and hybrids by stabbing them in a vulnerable area the base of the skull. The device is also effective as a stabbing weapon against humans. It is commonly used by Alien Bounty Hunters.
This type of weapon is made of an unidentified material that appears to be polished stainless steel. It is similar to a switchblade. It appears to be a small, thin, six-inch cylindrical device with a long rectangular switch or button that, when pressed, extends a long icepick-like protrusion that is used for stabbing. When this extension is released, the device emits a sound similar to a sudden jet of air being exhaled.
In 1995, Agent Fox Mulder was informed by a hybrid clone from the Samantha Series that the only way to kill an Alien Bounty Hunter is to stab him at his vulnerable point, at the base of the skull, on the back of the neck. These Aliens' ability to heal their body remarkably fast makes this the only effective way to stop them, as other wounds will not affect them. The stabbing needs to be done on this specific area, and if missed, the Alien will not die. The alien stiletto was thus invented to reach this area successfully, but precision is required, and an inexperienced user may fail to kill the Alien even if the stiletto is inserted there, as Mulder did with a Bounty Hunter pursuing Jeremiah Smith in 1996. Alien-human hybrids can be killed in this fashion as well. A closer look at this vulnerable point was made possible with the ill hybrid child Emily Sim in 1997. The small greenish protuberance was initially thought to be a cyst, and when a nurse inserted a needle into it to perform a biopsy, an abundant flow of caustic green blood was released, making the nurse ill, but leaving Emily unaffected.
When properly inserted at the vulnerable point, the stiletto immediately kills the alien or hybrid, who disintegrates into a puddle of green blood.
In 1995, an Alien Bounty Hunter used a stiletto when exterminating Gregor Series hybrids and a series of Samantha Series hybrids who worked in abortion clinics and attempted to lead colonization their own way. (TXF: "Colony," "End Game")
In 1996, when one of the Jeremiah Smith hybrids began to act against Syndicate instructions, a Bounty Hunter came forth to kill him with a stiletto. Agent Fox Mulder obtained such a weapon, hidden inside a lamp in his family's Quonochontaug residence. Mulder tried but failed to kill the Bounty Hunter. (TXF: "Talitha Cumi," "Herrenvolk")
In 1997, agents Mulder and Scully met a series of Kurt Crawford hybrids who had resolved to subvert the colonization project and gave the agents information about procedures performed on abducted women who had later contracted brain cancer. One such hybrid was destroyed with a stiletto by the Syndicate's Grey-Haired Man. (TXF: "Memento Mori") In the same year, hybrid doctor Ernest Calderon, who was treating Emily Sim, was also killed with a stiletto by the Syndicate's hybrid police for failing at his duty. (TXF: "Emily")
In 1999, a faceless alien killed and assumed the identity of the Second Elder. However, the Cigarette Smoking Man realized this and provided Jeffrey Spender with a gimlet weapon to kill him. Spender failed to do so, but Alex Krycek, who had followed him, succeeded. (TXF:"Two Fathers")
Also in 1999, Arthur Dales told Mulder about a colonist who, in the 1940s, had decided to push the colonization project aside and live his life as a human, passing off as a talented black baseball player named Josh Exley. The renegade Alien was hunted down by a Bounty Hunter and killed with a gimlet weapon. (TXF:"The Unnatural")
On the season 2 DVD special features, interviews detail the creation of the Gimlet sound effect, which was originally meant to sound like "alien technology" and went through a number of versions, usually highly processed "computerized" sounds, until it was finally simplified as the air exhalation sound.
The Gimlet Weapon acts like a weapon/item in The X-Files: Resist or Serve. It is acquired at the Red Falls Post Office, showing this X-File isn't involved in Witchcraft, but Alien Colonists. The item/weapon is used in the first boss fight in the game: a Purity-controlled Sheriff Bud Smith. Mulder has to weaken and stun him by shooting him with either his AK-47 or Pistol until his health bar is empty. When this occurs, Mulder must run up to him, look into his Inventory, select the Gimlet Weapon and then leave the Inventory. This will kill both Sheriff Bud Smith and the Purity controlling him. After it kills him, the Gimlet Weapon can't be used again in the game.