How to Beat the Behemoth in Abiotic Factor
The Behemoth is the supersized encounter waiting inside Abiotic Factor's Reactors zone, and abioticfactor.wiki.gg describes it plainly: it's "a red-colored variant of the Tarasque that is much larger in size" and "has all the same attacks and behaviors as the Tarasque." Same moveset, much bigger arena, and — unlike the Tarasque's containment — a room where it can leap farther, hit harder, and hide in total darkness. This guide walks through every stat, location, weakness, and drop the wiki documents for it, so you know exactly what you're walking into before you open the reactor chamber door.
What Is the Behemoth?
According to its listed stats, the Behemoth's codename is IS-0121-B, and its origin is recorded as Anteverse 42. Its health is split across two tracked pools: 2000 HP on the head and 1250 HP on the torso. The wiki doesn't state a single combined health total, but adding the two figures together gives 2000 + 1250 = 3250 HP across the creature as a whole.
Its attacks are listed the same way. The Melee Attack entry shows Damage 100, Type "Large Enemy" — quoted as written, since that field reads as an attack category rather than a damage type. The Smash Attack entry shows Damage "100/250", Type Explosive; the wiki lists both numbers without explaining what the split between them represents, so treat the exact meaning of the two figures as undocumented. Beyond "much larger in size," no specific size or scale figure is given for how much bigger the Behemoth is than a standard Tarasque — that comparison is also undocumented beyond the wiki's own wording.
Where to Find the Behemoth
The Behemoth is "found within the Dusk Reactor's chamber, lurking in a nearby corner" inside the Reactors area, and "becomes hostile upon noticing the player or any enemies." It's confined there: the wiki states it "is too large to leave the room it's trapped in and cannot jump onto the scaffolding," and that players "can use the corridors to escape in safety, or to attack from a place of cover" — the room's layout is itself part of how you fight it.
Before you ever reach the Reactors, you can actually see the Behemoth earlier: the wiki notes that "prior to reaching The Reactors, the Behemoth can be found in Containment Block Anning in Cascade Laboratories, in an inaccessible area," viewable only "from a window in the room where the Tarasque spawns." That sighting is not a fightable encounter — it's a preview, documented as inaccessible.
Combat Tips: Weaknesses, Resistances, and Tracking It in the Dark
The wiki calls this "a challenging fight" for reasons beyond raw HP. In the "wide open Reactor room," the Behemoth "can leap farther and higher than the Tarasque can in its containment," and "due to its tremendous size, its attacks impact larger areas." The room's "deep shadows" let it "catch unaware players by surprise" and make it "difficult to track in the darkness." On top of that, "the Behemoth's weaker flesh parts are nearly as strong as its full health, so the beast will be tougher to bring down overall" — quoted directly, since that's the wiki's own explanation for why this fight runs longer than the numbers alone suggest.
On resistances, the Behemoth "has all the same resistances and weaknesses as the Tarasque, so Fire and Electrical-based weaponry will deal additional harm." No specific damage bonus percentage is given for that — treat the exact size of the bonus as undocumented, only that it exists.
For visibility, two documented tools help: "Wearing NVGs and GATE NVGs will reliably reveal the Behemoth's location to a player." Separately, "under normal circumstances, the Behemoth is completely hidden in the dark," but "during Weather Events, players will be able to more reliably see the entity's location due to the changed visibility."
Harvestable Drops and Notes
The wiki's Harvestable Drops table lists exactly two entries, both at a 100% chance: 5x Tarasque Ichor and 1x Behemoth Skull. No other drop entries are listed, and no rarer or conditional drops are documented for this fight.
One trivia note is worth carrying into the fight for flavor rather than strategy: "the Behemoth is named after a primeval beast from the biblical Book of Job, being described as an incredibly powerful creature."
Practical tips
- Bring fire or electrical weaponry — the wiki confirms both deal extra damage, though it doesn't state the exact bonus.
- Equip NVGs or GATE NVGs before entering; they "reliably reveal the Behemoth's location" in a room where it's otherwise "completely hidden in the dark."
- If a Weather Event is active, visibility improves — use that window if you can time it.
- Use the corridors around the Reactor chamber to retreat or fight from cover; the Behemoth can't follow onto scaffolding or leave the room.
- Expect the fight to run long: its "weaker flesh parts are nearly as strong as its full health," per the wiki.
- The drops are fixed and guaranteed — 5x Tarasque Ichor and 1x Behemoth Skull, both at 100%, so there's no drop-rate gamble to plan around.
Running your own Abiotic Factor server
A fight like this goes smoother with a full squad watching each other's backs in the dark, and that starts with a stable place to play. A gamever Abiotic Factor server keeps your group's save online around the clock, so nobody has to leave a host's PC running just to keep the Reactors progress intact between sessions. Spin one up in minutes and use promo code WELCOME for a discount on your first month.
Conclusion
The Behemoth is a bigger, darker version of the Tarasque fight — same 2000 HP head / 1250 HP torso split, same 100 melee / 100-250 smash attacks, same Fire and Electrical weakness, but a wide-open room that lets it leap further and hide in total darkness until NVGs, GATE NVGs, or a Weather Event give you an edge. It's confined to its chamber and can't reach the scaffolding, so the corridors around it are your safety net. Clear it and you're guaranteed 5x Tarasque Ichor and 1x Behemoth Skull for the trouble.
Taking your group into the Reactors? Set up a gamever Abiotic Factor server and keep the run going 24/7.