About as tall or a bit taller than the average Irken, the typical Shock Spear seen in the show is purple in color, with small light grey parts near the top. At each end, there is a red sphere (Likely the emitter for the spear's titular shocking ability), and in the center there is a hand-grip.
On the bottom, the first sphere connects to a purple cylinder, then that to the main shaft of the weapon. In the middle sits the said hand-grip, and a bit further at the top is another cylindrical piece of the weapon. From it stems another cylinder or spherical section that protrudes slightly, and is darker in color, and two blades on opposite sides curve out. On the side with the protrusion, the blade points upwards; on the other side, the blade points downwards. The weapon ends with the other sphere.
Commonly, the Irken Shock-Spear is held singlehandedly like medieval-era pole weapons such as the halberd or poleaxe. In completed episodes, it has seen only one 'combat' use- shocking Smikka Smikka Smoodoo into submission after an attempted revolution ("Megadoomer"), and in this instance the guard only had to prod the Screwhead for an electric shock to flow over him.
However, judging by the condition of the screwhead after his shocking, it would seem the Shock Spear's shock is nonlethal - but likely very painful. It is possible that the shock settings can be altered, but this has not been seen.
One Irken guard was seen holding it in "The Voting of the Doomed" (pictured above) during Zim's daydream of winning the Skool election for student president, in which he imagines himself as Earth's (elected) ruler. Another time was the mentioned incident where another guard shocked Smikka Smikka Smoodoo into submission in "Megadoomer".