Get your first
Vrauk MK 02 from Phase 2 vrauk breeding program in a Reproductive complex. Each attempt has a 0.5% chance to produce one. After you have breeding stock, switch to the MK 02 cocoon and breeder recipes to multiply them.
1. Unlock the breeding program
Research Vrauks – Stage 2. The research snapshot used here lists 100 research units, each consuming 2 Automation science packs and 1 pY science pack 1, with 45 seconds per unit. Its immediate prerequisite is Fawogae – Stage 1.
Build a
Reproductive complex MK 01. The MK 01 complex is sufficient; an MK 02 building is not a requirement for breeding the MK 02 animal.
2. Prepare ordinary Vrauks and the inputs
Ordinary
Vrauk go in the complex’s module slots to make it operate. These occupants are separate from the ingredients consumed by the recipe. If the complex has its ingredients but does not run, check those slots first.
Supply cocoons, food, sap, Native flora and filled water barrels. One available cocoon recipe at this research stage is:
Vrauk cocoon
35 base seconds ·
Reproductive complex MK 01 · Cocoons are an average yield; the actual range is 8–12.
Reserve some ordinary Vrauks for machines instead of spending your entire colony as ingredients. You can inspect the original Creature chamber acquisition recipe on the
Vrauk page.
3. Run Phase 2 until you get MK 02
Phase 2 vrauk breeding program
30 base seconds ·
Reproductive complex MK 01 · Fractional animal outputs represent probabilities, not a guaranteed animal each batch.
The MK 02 output is one animal with a 0.5% chance per completed attempt. A displayed average of 0.005 is the expected yield across many attempts. The base recipe time is 30 seconds; actual completion time depends on the complex’s crafting speed and occupants.
Automate the five returned empty barrels back into water filling, keep the other inputs supplied, and collect the rare MK 02 output separately from ordinary Vrauks. Leave output space for every result.
Calculated from independent 0.5% attempts: 1 − 0.995ⁿ. 200 attempts is the average wait for one success, with about a 63% chance of at least one. Even 600 attempts is about 95%, not a guarantee.
4. Turn the first animals into a colony
Keep running the Phase 2 program until you have at least two MK 02 animals for the cocoon recipe. Store a reserve if you can. A
Vrauk paddock MK 01 can run the next recipes; put suitable Vrauks in its module slots as well.
Vrauk cocoon MK 02
60 base seconds ·
Vrauk paddock MK 01 · Average animal return 1.98; keep replacement stock.
This recipe makes 4–7 MK 02 cocoons and attempts to return the two parent animals at 99% probability. Parents can be lost. Once you have enough cocoons, run:
Vrauk MK 02
60 base seconds ·
Vrauk paddock MK 01 · 1 parent returned plus a 95% chance of 1 extra animal.
The breeder returns the one input parent and has a 95% chance of producing one additional animal. Its 1.95 output is an average total, not 1.95 new animals. Feed some offspring back to cocoon production and keep the surplus for machine modules.
Why is it stuck?
- No progress: check module occupants, power, filled barrels and all five ingredients.
- Only ordinary Vrauks: confirm the selected recipe is Phase 2 and allow for the low success chance.
- The tree seems circular: the cocoon and breeder routes maintain existing stock. Use Phase 2 to bootstrap your first MK 02 animals.
- It ran and then stopped: check barrel handling, food supply, output slots and whether the cocoon recipe lost a parent.
Sources, versions and checking
Written from the guide’s recipe export and installed Factorio prototype data, checked 11 November 2026. Recipe quantities use the FactorioLab full-suite snapshot retrieved 3 November 2026 (Factorio 2.1.21, pY Alien Life 3.1.8). Fuel behavior and breeding probabilities were checked against installed Factorio 2.1.24 prototypes with pY Alien Life 3.1.8. Research costs use the guide’s separate resolved technology snapshot.
This is a data-checked walkthrough, not a recorded playthrough. Startup settings, other mod versions and different mod combinations can change recipes. Quantities shown with fractions are expected yields. Base recipe seconds do not include machine speed, fuel or electricity. Follow the linked item pages to compare alternatives.
