As promised, the Lixer headcannon
The Nixels created the Lixers out of disposed Mixel parts (why they know what the three look like as opposed to Muncholand's guys) as a sort of "Fight fire with fire" strategy. Create a mixel tribe, make them hate their "normal" counter parts, and then set them loose on the Mixels. Unfortunately this backfired.
Their first experiment, Turg, was more or less a success! It was sentient, strong, able to learn, able to communicate more or less, and hated other mixels with a passion. It also hated nixels but was smart enough to bury this fact when they were present. Tungster and Spugg on the other hand... weren't that.
Spugg was just a puppy, a normal dog and didn't see a difference between Mixels and Nixels, she liked them equally, while Tungster was sentient and able to learn (not able to speak but able to sign and write) hated Nixels and wanted to be among other Mixels. Both were deemed failures.
Turg grew attached to its fellow experiments since, well, they were basically its family, so when it overheard that their disposal was imminent, it decided to stop being the "perfect experiment" and started to actively show aggression towards its creators. When it eventually found a cubit, it maxed with the other Lixers and destroyed the lab and every nixel in it.
That basically sums it up! They kinda stayed in the swamp because they had no where else to go. Only Kamzo knew about them for the longest time (until QFTLM), and that's only because he was attacked by Turg for tresspassing.
