The creator of this Species claims to have found them after leaving random cell contamination and low levels of radiation for awhile. He then modified and perfected them.
UPKCs are composed of three cells. The Keratinocyte head, Photocyte body and Flagellocyte tail. Depending on the light amount, UPKCs can have many cells, but in a 0.460 light amount environment the UPKC can achieve ~26 body cells in it's full form.
The Keratinocyte head first makes a single body cell. The body cell gives it more energy and the head starts making more bodycells until developing into it's full form. When body cells get big enough they die and turn into a tail which is a lone flagellocyte that dies off by swimming until starving (this is the way the UPKC deals with not needed cells). After reaching it's before mentioned full form it will keep disposing of big and old cells and mobilize extremely slowly. The UPKC will never divide or die off unless it's affected by other cells.
That is the UPKC's normal lifecycle. But the UPKC has various strange reactions seemingly random or caused by other cells, sometimes by other UPKCs.
The first reaction is unstability, after hitting something or getting some of it's cells eaten the UPKC's body cells will be shuffled instead of the standard 3-cell thick body and the cells will divide one by one instead of three at once. Use this last feature to easily recognize these. Unstability can lead to three possible other states, the first one, and the most common by a 90% of times, is that many of the unstable UPKC's cells will all die at once, making the UPKC head regrow it's whole body and go back into healthyness. The second is the second most rare, being that the cell will die after ALL of it's cells die at once and the head has no food. And the third and most rare which is also a theory, is that the UPKC goes into exploding state; after killing many of it cells, the head regenerates the body cells but disorderly causing the head to die due to being squished and all the cells divide (not die) into flagellocytes, causing the "exploding" effect.
The reasons behind why the UPKC enters eploding state is unknown, there are many theories made by it's creator: the exploding reaction could be a bug caused by too many UPKCs in the screen in incubation view (due to it being more common in these circumstances), it could be caused by the unstable reaction, or just be caused by hitting another UPKC or cell at a high speed.
The UPKC have a very peculiar relation with predatory organisms like Devorocytes for example, since they cannot kill the UPKC because of it's Keratinocyte head. They can only kill it by getting completely rid of all it's Photocytes it uses to feed or it's Photocyte connections. If the head is not destroyed and has enough food it will regrow into another full UPKC.
If you want to study or see the UPKC by yourself, look for the UPKC mode screenshots to recreate it and microscope screenshots to see it.
The UPKC MUST have a 0.4 to 0.5 light amount in order to function properly. The rest of the options can remain unchanged.