Not all of the life forms in Doodle are native to that plane of existence. Through some improbable fluke of physics, a small number of earthly life forms have physically entered Doodle, with an even smaller number managing to sustain a population. These are all incredibly simple organisms. Doodle is a harsh environment even for its native life forms, and nothing as large and sensitive as an Earth vertebrate could survive for any length of time.
Populations of non-native life are clustered around Doodle being carcasses, as the blob matter they are made from is extremely calorically dense, and rich in proteins and sugars. Bacterial life is the most abundant, followed by things like microalgae and fungi, and finally mesofauna like springtails and proturans. None of these things are visible to the naked Doodle being eye, so they do not know they exist.
The largest and most complex example of a naturalised species in Doodle, and one that the Doodle beings are very much aware of, is Musca domestica doodlei, a subspecies of the housefly that has become adapted to reproducing inside and living around carcasses.
Since the flies are seen emerging from or flying around deceased Doodle beings, they are universally associated with the deceased in Doodle culture. Flies are dubbed "angels," and may be ascribed a psychopomp-like significance as guides to the deceased, or heralds of death. Radically different in appearance from anything else a Doodle being can encounter in their environment, flies trigger an emotion similar to the human concept of “the uncanny valley.”