For example: War Of The Worlds, Mars Attacks!, The Faculty, Signs

The first rule of hostile alien first contact is that conventional weapons are generally useless. If the army are called in, they will fail against the alien menace (sorry, guys!). The second rule is that bizarre everyday substances or items will turn out to be more helpful.

The common cold, hip designer drugs or good old water may turn out to hold the key – so in extremis try sneezing on them, or offer them a hit of something illegal with a tall cool glass of H2O to follow. If none of those options work, start going through your record collection; we recommend Slim Whitman’s Indian Love Call, which is effective against at least 10 percent of Martians.