Complex sentence: Stationary attractive bioluminescent stalks appear in large numbers throughout Xen, which retract when approached, and like several Xen organisms, it is uncertain whether these should be considered plants or animals.
Split into simpler sentences: Stationary attractive bioluminescent stalks appear in large numbers throughout Xen. They retract when approached, and like several Xen organisms, it is uncertain whether these should be considered plants or animals.