When fired at an enemy, the beam from the Atomos will link between multiple adjacent enemies within 3 meters of the initial target and each other, and any caught in the width of the beam will also be damaged. It has a small radius of damage around the beam, similar to the Ignis and Embolist.
The Atomos can chain between enemies a maximum of 3 times, for a total of 4 enemies hit simultaneously including the original target.
The Atomos's beam will not chain to a Nullifier through its shield should it connect with a target outside or partially enclosed by it.
The beam can also continue to chain to enemies even if targeting a dead enemy or an enemy who is dead but in a dying animation. This makes punch-through completely unnecessary on the Atomos as dead enemies do not prevent the beam from connecting.
Comparing just base statistics, the Atomos is nearly identical to the Gammacor (not to be confused with Synoid Gammacor). However, the Atomos has shorter range, strikes multiple targets through chaining (similar to the Amprex), and has double the status chance (10% vs 5%).
The Atomos's innate Heat element is positioned last when adding elemental damage mods to the weapon.
The Atomos covers up part of the reticle when aiming. This combined with the beams behavior of slowly rotating around a central point means that occasionally the beam will fire behind the weapon with no way of knowing if you are aiming at the enemy or not.
Ruinous Extension can be used to extend this weapon's reach, allowing it to hit targets further away. In addition, it also applies its full effect to the chaining property, allowing the Atomos to more easily hit multiple spread out enemies.
Before the release of Atomos, the closest one could get to this effect was with using a Tysis that was heavily modified for Heat and Status Chance.
Ground-based enemies (e.g. CorpusCrewmen, InfestedChargers etc.) slain by the Atomos will char or appear to be coated in ash, and then disintegrate. Like the Glaxion's special effects, this effect occurs even if the Atomos is modified to deal a different kind of damage.
When reloading, two sections are removed and subsequently replaced individually, unlike other weapons. It can be speculated that one could be fuel and the other an igniting agent or propellant.
The Atomos's visual effects will not go through Volt's Electric Shield, but it will interact with the shield normally (critical damage bonus, range boost, etc.)
When crafting in the Foundry the Atomos will use the model of the Mire
If a Tenno is currently firing the Atomos when they are revived from the downed state, the visual and audio effects of the beam may become stuck at that position and randomly target enemies or even fellow allies for the remainder of the mission. (If stuck to a Tenno it will follow them all the way to extraction, resulting in further eyesore as it clips through the entire map and all terrain to do so.)
However the bugged beam does no damage and is purely an aesthetic issue.