AEGIS (Portal Stories: Mel)

AEGIS is the antagonist of the Portal mod Portal Stories: Mel. AEGIS stands for Aperture Employee Guardian and Intrusion System, and it's a simple AI system in charge of protecting the employees of Aperture. It failed that mission when GLADoS killed all the scientists in the facility with neurotoxin, and the main plot of PS:Mel is that Mel needs to escape before AEGIS destroys the entire facility to kill GLADoS for good and avenge its wards.

I really love its design because of just how tactile it looks. Compared to every other system in 'New Aperture', AEGIS still carries the old look of the old company, since it was clearly made long before the sleek, modern designs that informed the newer AIs of the games. It still runs on magnetic tapes for all its processing power, it sees through old clunky box cameras, its worn down and scratched unlike anything else in the new facility. Just a system that was grandfathered in, much like the protagonist, Mel.

The entire thing with PS:Mel is that Mel was originally a beta concept for the protagonist of Portal 1, and just like Mel, AEGIS' design comes from a beta concept of GLADoS! There were sketches early in Portal's development where GLADoS had a spider-like design, and with the bulbous body, wires stretching into the ceiling, and the shadows of the girders keeping AEGIS suspended, it also invokes that spider silhouette.

Old Aperture was always my favorite area of Portal 2 just because of how it contrasted with New Aperture, and AEGIS exemplifies that with its old lair being moved to the middle of New Aperture, next to the smooth white turrets and moving panels.

Plus, AEGIS' boss music is a banger