1.   The teacher might play an alien who could not communicate at all with the crew members and wanted to learn their language.

2.   Hamill and Richard Grieco play aliens living on Earth.

3.   He plays an alien sent to earth to impregnate a woman, thus giving his people a foothold on the planet.

4.   Lithgow, who plays an alien, said he believes in aliens.

5.   You can see why Kevin Spacey, the keenly observant, hyper-realistic actor, would jump at the chance to play an alien from outer space.