Takunitagaminituron
From The Stargate Omnipedia
A Goa'uld automatic remote weapon approximately 12 centimeters in diameter, also known as a "tak", which senses motion and fires quick blasts of energy. Taks are hidden in an area as a security system, firing on unsuspecting trespassers when they approach.
Though the device is similar in design to a shock grenade, the two weapons perform very different functions.
KEY EPISODE
Deadman Switch - O'Neill and Teal'c disable a group of taks that the Tok'ra Korra has set up to guard his hide-out.