space invader
alienesque
alienly
allotrious
other
ayy
cosmogenous
foreign
spaceling
unidentified flying object
xenomorph
xenophysics
Pleiadean
xenotechnology
alienism
bug-eyed monster
space alien
starman
visitor
xenoengineering
extraterrene
eetee
ultratelluric
xeno-
wight
substar
xenology
xenohistory
alienness
astrohistory
xenogeology
xenomorphology
supraterrestrial
moon-man
xenobacteriology
xenoscience
exocommunication
star visitor
xenomythology
extraterrestrial
space biology
exobiology
xenomicrobiology
astrobiology
xenopsychology
alienish
spacy
alienage
alienkind
extraterrestrialization