Answer:

ets

AnswerCrossword Clue
ETSAlf and Mork
ETSLittle green men
ETSSaucer contents?
ETSSaucer's contents, for short
ETSUFO pilots
ETSSci-fi figures
ETSSpock and Mork (Abbr)
ETSUFO passengers
ETSSpace invaders, briefly
ETSUFO crew
ETSMork and ALF
ETSUFO's crew
ETSUFO crew?
ETSSci-fi beings
ETSS.f. characters
ETSVisitors from space
ETSUFO pilots, maybe
ETSArea 51 creatures
ETSTOEFL administrator
ETS"Star Trek" extras?
ETSGRE administerer
ETSLittle green men, for short
ETSVisitors from afar, for short
ETSAliens, briefly
ETSSci-fi staples
ETSUFO occupants, so some believe
ETSUFO pilots, presumably
ETSAliens, for short
ETSSaturn drivers?
ETSSci-fi film extras
ETSSome "Twilight Zone" creatures
ETSSome special FX projects
ETS"Men in Black" concerns
ETSTV's ALF et al.
ETS"The Outer Limits" extras
ETSSome aliens, familiarly
ETSThe Coneheads, e.g.
ETSThey travel a long way to get here
ETSThey're not from around here
ETSInfiltrators among us, some say