An emergent lifeform was a form of life created through the unpredictable behavior of a complex system.
In 2370, the USS Enterprise-D was taken control of by a network of semi-intelligent emergent circuit nodes that required vertion particles to create a new emergent lifeform. The Enterprise crew eventually cooperated with the emergent electronics to assist in the creation of the lifeform. The circuit nodes disappeared once the lifeform was complete, and the lifeform itself disappeared into space. Although Data wondered if they had made a mistake in allowing the lifeform to develop, Captain Jean-Luc Picard argued that, if the creature was based on the records available in the Enterprise databanks, he felt reasonably confident in assuming that the creature would be as honorable as the records that played a part in its creation. (TNG: "Emergence")