Passport

The Passport is an item mentioned all the way in the beginning of Act 1 by Benry, in which he demands to see Gordon's, and later becomes an important piece of the series' plot. Thanks to Gordon's confusion when demanded to show his, the Passport appears to have been enforced through a very new security protocol, in which it is necessary to have one's passport in order to traverse Black Mesa. Despite this, very few scientists or security personnel appear to have their passports except for Benry, Dr. Coomer, Dr. Bubby, Tommy, the Skeleton, Gordon, and the G-Man (although several of these did not have their passports on them, but owned one).

In Act 4, the Passports double as an important key item the crew must destroy in order to defeat Benry, all of which are guarded by various means. Tommy's passport was guarded by the Skeletons, Bubby's passport guarded by the Prototypes, Dr. Coomer's passport guarded by Mokujin from Tekken, and Benry's passport being held by himself, all of which were eventually destroyed. Gordon's passport required he be sent back in time and into an alternate dimension in order to destroy it himself.

Trivia

 * This is one of two items required by staff at Black Mesa to traverse it freely (the other being a Black Mesa Silly Straw™).


 * The Passport seems to also double as a gun. Benry, in particular, is repeatedly shown to use it to fire a barrage of Dark Energy Balls, which can vaporize enemies instantaneously.
 * The Passport is implied to give Benrey his powers, as destroying all of the known passports, including his own, allowed for Benrey to be defeated in the final fight.
 * Despite this, one Passport is seemingly left behind, that being one belonging to a Skeleton named "You," seen earlier in the series. It is likely this was ignored to save time for the finale, or ultimately forgotten about.
 * The model used for the passport in the final act is an actual pre-existing model found within the workshop of Garry's Mod, having been merely retextured for its purpose on the show.