
A semi-truck might be an ALIEN robot...
The Big Bang Theory Season 6, Episode 2

Last night, Raj accidentally made
contact with an ALIEN civilization...
The Big Bang Theory Season 4, Episode 9

When I encountered ALIEN life, I discovered
that the key thing was not to sit in its spot.
The Big Bang Theory Season 8, Episode 21

...from Earth in case one of them
is encountered by ALIEN life.
The Big Bang Theory Season 8, Episode 21

...he's allergic to Earth nuts,
but I'm the ALIEN.
The Big Bang Theory Season 8, Episode 21