Captive biter spawner

A captive biter spawner is a placeable entity used to produce biter eggs, and it is the only source of biter eggs in the game. It functions as a living production building rather than a normal crafting machine: it does not require a recipe, and it only needs a constant supply of bioflux to keep working.

A captive biter spawner produces 5 biter eggs every 10 seconds for a rate of 0.5 eggs per second. It can store up to 100 eggs in its output slot. When that slot is full, the production cycle keeps running, but no additional eggs are created until space is available. Eggs held in the output slot do not begin spoiling until they are removed, and once removed they cannot be inserted back into the spawner.

The first way to obtain a captive biter spawner is to fire a capture bot rocket at a biter spawner on Nauvis. The capture process takes 20 seconds, and during that time the bot can be attacked and destroyed by nearby biters. The spawner continues producing biters while it is being captured. After reaching Aquilo and researching captive biter spawner, the player can also craft them directly and place them manually. A captive biter spawner in an inventory or container has a spoil time of 30 minutes, after which it turns into a behemoth biter.

A captive biter spawner needs constant food input. If it stops receiving bioflux, it stops producing biter eggs and loses 1 health per second, regardless of quality. If its health reaches zero, it reverts into a normal biter spawner with full health and must be captured again. While consuming bioflux, it repairs itself at 1 health per second. One bioflux has an energy value of 6 MJ, and because the spawner consumes 100 kW of food, a single bioflux lasts exactly one minute, independent of freshness. Since a normal quality bioflux item lasts two hours before spoiling, up to 120 items of the same age can be fed to a single captive biter spawner before any of them spoil.

Captive biter spawners that have previously been captured and then starved are not targeted by automated weapon systems, including turrets and artillery, except for rocket turrets and spidertrons loaded with capture bot rockets. They still consume pollution and continue to spawn biters, and those biters are affected by the evolution factor.

Quality does not improve the quality of the biter eggs produced. However, if a captive biter spawner reverts back into a biter spawner for any reason, it retains its quality. The resulting spawner then spawns biters of the same quality, and those biters can form expansion groups that also keep their quality when they successfully expand, creating more quality biter or spitter spawners and even quality worms. If such reverted spawners are not contained, they can spread higher-quality enemies across the planet.