Spitter Nest

Lore & Background

The Spitter biome is a region of the Factorio world where the soil and flora have been saturated with a caustic, bio-luminescent green sludge. The air shimmers with a faint yellowish haze, and the terrain takes on a sickly, wet sheen that distinguishes it immediately from the grey-brown of the Bitter zones. Within this toxic landscape, the Spitter Nests grow like grotesque fungal blooms—pulsing, glistening masses of organic tissue that seem to breathe with a slow, wet rhythm. They are not built; they are grown, and they are rooted deep in the poisoned earth. The Spitters that emerge from these nests are not animals in any conventional sense. They resemble twisted, stalk-like organisms with bulbous heads, their bodies a mottled green and yellow. Where a Biter lunges and bites, a Spitter rears back and expels a glob of searing acid from its mouth. The projectile arcs through the air with a faint hiss, and where it strikes, metal corrodes and flesh burns. The small Spitters are quick but fragile; the Medium Spitters are tougher and hit harder; the Large Spitters are slow, lumbering horrors capable of vomiting multiple streams of acid in rapid succession, turning a patch of factory floor into a smoking ruin in seconds. In the ecology of the hostile world, the Spitter Nests represent a parallel evolutionary pressure to the Biter Nests. Where Biters overwhelm through numbers and speed, Spitters punish through range and chemistry. A player who has mastered the art of walling off a Biter nest may find their carefully constructed perimeter utterly useless against a Spitter Nest, because the acid does not need to reach the wall's base—it simply needs to arc over the top. The two enemy families, together, ensure that no single defensive doctrine is invincible.

In Their Own Story

The survey drone's last transmission was a burst of static and the faint, wet sound of something hissing. Engineer Vasquez watched the feed die and felt the familiar cold knot in her stomach. The Spitter biome stretched ahead of her, a vast expanse of glistening green ground under a sky that seemed to bleed yellow at the edges. She could see it now, even from this distance: the Nest. It sat in a shallow depression in the earth, a swollen, veined mass the size of a small building, its surface rippling with slow peristaltic waves. A thin tendril of acid dripped from its central maw and sizzled where it hit the rock. She had three turrets placed in a rough triangle around the extraction point. The blueprints said that should be enough. The blueprints, she was beginning to suspect, had never met a Large Spitter. One of them was already emerging from the Nest's opening, its stalk uncoiling with a sound like wet leather stretching. It turned its bulbous head toward her. It did not charge. It simply tilted back, and a bead of glowing green acid formed at the tip of its maw. Vasquez hit the turret override and prayed the reload cycle was faster than the arc.

Reader's Guide

Spitter Nests are large, organic structures with a bulbous, fleshy appearance, colored in shades of sickly green and yellow. They sit low to the ground with a prominent central opening from which Spitters emerge. The surrounding Spitter biome is visually distinct: the terrain has a wet, glistening green tint, and the overall atmosphere carries a faint yellowish haze that sets it apart from the grey-brown Biter zones. Spitters come in three sizes. Small Spitters are quick and fire a single acid projectile. Medium Spitters are tougher and hit with greater force. Large Spitters are slow but can expel multiple acid projectiles in rapid succession, making them the most dangerous tier. All Spitters are ranged: they do not close to melee but instead halt at a distance and lob acid in a short arc. This means they can damage machines, belts, and the player even when partially behind walls or terrain features. Spitter Nests spawn Spitters continuously over time, and the rate and strength scale with the global evolution stage. They appear in the Spitter biome from the earliest stages of play, but their threat compounds as evolution progresses. Because Spitters attack from range, the standard Biter-defense strategy of a simple wall perimeter is insufficient. Effective countermeasures include placing turret clusters at sufficient range to engage Spitters before they can fire, using elevated turret positions, and maintaining a buffer zone between the Nest and critical infrastructure. Walls still help by forcing Spitters to arc over them, but they do not block the projectile entirely. In the broader enemy ecosystem, Spitter Nests are the ranged counterpart to Biter Nests. They do not swarm; they siege. A well-defended Biter nest can be overwhelmed with a few turrets, but a Spitter nest demands that the player account for projectile trajectories, acid damage to machines, and the possibility of multiple Spitters firing in overlapping volleys. They are, in essence, the enemy that punishes complacency.

Did You Know?

• Spitters are the only enemy type in base Factorio that attacks from range, making them a fundamentally different tactical challenge from the melee-focused Biter family.
• The Spitter biome is visually and mechanically distinct from the Biter biome, with its own greenish terrain tint and atmospheric haze, and the two biomes do not overlap.
• Large Spitters can fire multiple acid projectiles in quick succession, creating a short burst pattern that can shred multiple machines or the player in a single volley.
• Because Spitters attack with arcing projectiles rather than melee bites, a wall that completely blocks a Biter can still be overtopped by a Spitter's acid, requiring a different defensive layout.