With the reach of the Internet, it's not very hard to find screen tests and see how our favorite characters were born. We've got everything from Marlon Brando testing for 'Rebel Without a Cause' to Gerard Butler donning a crappy wig and vamping out for a 'Dracula 2000' audition. Some, like Brando, offer iterations we never got to see in all their glory, some just seem too silly or awkward to imagine, and then there are some where the test is just so perfect you can't believe it -- especially when it's not a well-known actor strutting their stuff for the audition camera.

As the comprehensive Alien Anthology Blu-ray gears up for release, we've got two looks at Sigourney Weaver's killer screen tests for 'Alien.'