As you probably know, none of these creatures appear ordinarily in GTA: San Andreas, so you would need a mod. Suggest you have a look at this site to see if it can help you further:
www.moddb.com/mods/gta.../how-to-install-mods-in-gtasa
There may well be mods available for Alien and Bigfoot in GTA: San Andreas. Suggest you have a look at this site for more information:www.gtagaming.com/sanandreas
Grand Theft Auto: San Andreas user-made modifications are available for the PC version of the game only.
There are no aliens ordinarily in GTA: San Andreas. You could check on the internet to see if there is a mod available for this (would have to be done on a PC though). Suggest you look on the modification section of gtawiki if interested: gta.wikia.com
Bigfoot is possibly an alien entity as illustrated by solid UFO cases.
No there is not, I hope this helps! This is GamespotHQ.
Battle of the Planets - 1978 The Alien Bigfoot 1-60 was released on: USA: 19 November 1979
Alien Paranormal Bigfoot UFOs and the Men in Black - 2013 was released on: USA: 1 June 2013
there isnt any
These are my faves angry birds i pint alien milk contract killer pacman grand theft auto iv
It's just like bigfoot, nobody knows.
In the corner with Bigfoot and the Loch Ness monster hiding from werewolves and vampires.
um you can't get alien on gta san andreas on gta san andreas mod only maybe?