Gachas are essentially living lootboxes and resource farms. They will eat anything (including stone, wood, or fiber) and turb it into crystals which can drop a variety of resources including black Pearl's, organic polymer, or obsidian, among other things. They also have a rare chance to drop higher-tier crystals which turn into upgraded armor and tools
In order to get the tamed Gatcha to drop loot crystals make sure you have owl pellets and stone in its inventory. 1 owl pellet + 20 stone per loot crystal. If you have tamed snow owls just park them near the gatcha and the gatcha will pick up the pellets automatically.
Gachas throw temper-tantrums when not mate boosted. So remember if you want to farm them keep them far apart from same sex gachas and each should have their own mate. Ex. 2 f and 1 m can make them get jealous with purple lights and vise versa.(they will refuse to take anything and won't produce anything.
Day 1: Gatcha dropped ramshackle riot boots, ASCENDANT TORCH, metal behe gate, MASTERCRAFT LONGNECK, journeyman shotgun, apprentice pump shotgun, and journeyman assault rifle. Was a good day for just dropping stone on the ground XD