Note this is at theory and is not certain. Also parts of the story may be somewhat disturbing to some.
Part One: The story of Doug Rattmann
Doug Rattmann, also known simply as Rattmann was a aprature labs staff member. He was the only one to survive Glados poisoning everyone's food. The poison caused him to go a little off the deep end if you know what I mean. After this he depended on anti psychotic meds. When Dougie boy's meds ran out he went completely insane. He started talking to the companion cube (a never before living thing (or is it)) and acting like it was a person. In the Portal comics he somehow got advice from the cube. Without it he almost got himself killed. Warning this is when it gets a little creepy.
Part Two: Glados' possible secret
Glados, a robot that works in aperture labs, should never be trusted. I will tell you why. Glados is your enemy, and almost everything she tells you is false and you should do what she says not to. Also she refers to you as useless and terrible. Glados also talks in the same way about the companion cube.
Part Three: The Truth?!
Let me just tell you this. The companion cube is composed of THE DEAD BODIES OF PAST TEST SUBJECTS!!! Who would guess that? Nobody. But I have proof.
