xenobiology
xenoscience
xenopaleontology
xenobiochemistry
alien
xenomorphology
xenoengineering
xenology
exocommunication
xenotechnology
exogenesis
extraterrestrialization
UFO
unidentified flying object
flying saucer
xenocytology
xenophysics
exobiology
astrobiology
xenogeology
xenomicrobiology
space biology
bug-eyed monster
xenochemistry
benthic
benthophil
extraterrestriality
eetee
space invader
xenobacteriology
ghost
space alien
alienkind
bolide
xenomorph
visitor
xenopsychology
xenoanthropology
alienism
entity
xenozoology
astrozoology
ayy
substar
parabiosis
xenoethics
ancient astronaut hypothesis
paleocontact hypothesis
extraterrestrialness
xenoarchaeology