Energy cell (Doom)

An energy cell is an ammo container used to power the plasma gun and the BFG9000 in Doom and Doom II, and additionally also the Unmaker in Doom 64. In the original games it is depicted as a small dark gray container shaped like a box and displaying small green lights or s, while in Doom 64 it looks more like three different ammo containers attached together. It holds enough energy to fire the plasma rifle 20 times (or 40 on the I'm Too Young To Die and Nightmare! skill levels). While the plasma gun can be discharged one unit at a time – with difficulty, due to its rapid rate of fire – each BFG shot consumes 2 whole cells (or 1 on NM and ITYTD). The Unmaker on the other hand has a different ammo consumption depending on how many Demon Keys the player has collected, ranging from one at zero keys to three at full keys.

Each shot from the plasma gun does 5-40 hit points of damage, determined using Doom's pseudorandom number generator. BFG damage calculations are more complex; a direct hit inflicts 100-800 points, after which additional energy damage is discharged, that can take the total damage into the thousands of hit points. Each attack from the Unmaker (visually a laser but in practice a hitscan attack) deals between 10 and 80 points of damage.

Appearance statistics
In the IWADs the energy cell is first encountered on these maps per skill level:

The IWADs contain the following numbers of energy cells per skill level:

Doom RPG
In Doom RPG, the plasma pickup is called a plasma box. It gives the player either 4 or 10 cells.