This paper model is a full size Zat'nik'tel (nicknamed Zat or Zat Gun by Colonel Jack O'Neill), a handheld weapon used by the Goa'uld and their Jaffa. It is in the shape of a serpent and was first encountered by SG-1 on Apophis's Ha'tak, based on the Stargate TV series, the papercraft is created by Artem Kotovsky.
In recent years, the zat has become a second back-up weapon for personnel assigned to the teams of Stargate Command and who often go off-world with the zat itself often being seen in the thigh holster of various teams with one notable example being Captain/Major/Lieutenant Colonel Samantha Carter who during her tenure on SG-1 was seen wearing a thigh holster with a zat inside.
In addition, security guards assigned to the SGC also use the weapon as a means of protecting themselves if they run into any difficulty or if they need to sedate a prisoner who has escaped the custody of the SGC.
You can download this paper model template here [Note: No Instruction!!!]: Stargate - Full Size Zat'nik'tel (Zat Gun) Free Paper Model Download [Box] [Gavitex]