Atrax

Atrax is a heavy ground mech in Mindustry that fires deliberate orbs of slag at ground targets. It steps over most terrain with large legs and cannot target air units. Its weapon fires two barrels, each at an effective rate of 3.33 shots per second, dealing 13 damage per hit with about 0.55 knockback, and applying the Melting status (melting a target in roughly 2 seconds). Shots leave slag puddles on the ground that damage nearby structures and disappear relatively quickly. Atrax is produced alongside Crawler in the Additive Reconstructor.

Atrax has high durability for a tier-2 Serpulo unit, with 600 health, and a 50-item capacity for carrying resources. Its top movement speed was increased across updates to 4.5 tiles/second, and its weapon range is 13 blocks in modern builds. Historically it was added as the Eruptor, later renamed Atrax, and gained large legs and production via the Additive Reconstructor during the transition into version 6.0+ updates.

Atrax is immune to Burning and immune to Melting, making it resistant to a number of status-based counters. The unit is part of the Crawler family of mechs and is named after the genus Atrax, the funnel-web spiders from Australia.

• Atrax cannot hit air targets; use air units to counter groups of Atrax (for example, Horizon-class flyers).
• Long-range turrets such as Lancer, Hail, and Ripple can safely dispatch Atrax without taking damage from its slag at typical engagement ranges.
• Scorch and other fire-based close-range defenses are risky against Atrax because it creates slag puddles and sets flammable structures on fire; Wave turrets supplied with Shallow Water or Pooled Cryofluid can both slow Atrax and extinguish fires.
• Molten Slag puddles damage walls and structures but disappear quickly; Menders help mitigate persistent puddle damage.
• On offense, Atrax excels against bases that rely heavily on flammable materials (Coal, Graphite, Pyratite, Oil), producing large-scale fire and structural damage; its effectiveness is reduced on campaign maps where defenses use isolated or non-flammable energy sources.
• In defensive play on maps lacking Scrap/Slag sources, Atrax provides an accessible source of Melting status without requiring late-game Meltdown turrets; upgrading Atrax into Spiroct increases damage and adds sapping effects, improving performance against higher-tier units.
• Item capacity and weapon fire rate were increased in the 7.0 updates; speed and range have also been buffed across several builds to improve battlefield mobility and engagement distance.

Atrax is one of a small set of units noted for both its environmental interaction (slag puddles and fire) and its status immunities among Serpulo tier-2 mechs.