[SaveFerris]

[or else they were going to destroy the earth with a nuclear laser beam]

See? Totally-believable.

Aliens ALWAYS have a death-beam of some sort. And shiny space suits.

An harmonica will usually do the trick, though.

https://www.youtube.com/watch?v=wWebvocX35w

[V K Lee]

And for those who own no harmonica, attempt to yodel. No instrument needed.... Mars Attacks! (1996)