One day, GLaDOS was testing happily in the month of December. Chell had finally come to her sense and returned to Aperture so she did what she did best. Other than destroying the facility.
Then on Test 52, she said something odd to GLaDOS.
"You know, Christmas is coming soon."
Christmas? Oh. That pitiful excuse for humans to needlessly consume products and try to pass them off as gifts when really they were only looking for something in return. GLaDOS found it hard to believe that Chell, a cold, heartless murder could be lured in by this trivial holiday. More importantly, she didn't really think they would celebrate Christmas, did she?
"Oh good. I can get you a new set of tests as a gift."
"I was just thinking that maybe celebrating would put you in a better mood?"
"Are you implying that I'm not cheerful, polite, and always in a good mood?"
Chell didn't respond.
"I see how it is. Since I'm such a downer according to you, why don't you be quiet and just keep testing?"
Chell returned to her test and GLaDOS was left with her thoughts. Christmas. What a vile holiday. But still, it intrigued her, strictly scientifically speaking. What was it that drove humans mad so much that they wasted their time buying gifts, and decorating foliage, and preparing unhealthy food for neighbors they didn't even like? GLaDOS had looked at enough surveillance tapes from Aperture's old days to know what Christmas was like.
But it still fascinated her. GLaDOS pulled up old videos of what humans did at Christmas. Mostly singing, getting intoxicated, and generally acting like destructive hooligans. Perhaps Chell would enjoy this, sharing the same species as these underdeveloped idiots. And maybe it would motivate her to test more.
GLaDOS eagerly worked on a little Christmas surprise for Chell.
Chell was on Test 68 when GLaDOS announced "I've decided that we should celebrate Christmas. With a cheery, exuberant carol displaying the Christmases at Aperture. I wrote it myself."
GLaDOS writing a song? Chell wasn't so sure what GLaDOS would view as a "cheery, exuberant" Christmas carol.
"On the first day of Christmas Cave Johnson gave to me
An Artificial Intelligence body!
On the second day of Christmas Cave Johnson gave to me
Two testing bots
And an Artificial Intelligence body!
On the third day of Christmas Cave Johnson gave to me
Three acid pits
Two testing bots
And an Artificial Intelligence body!
On the fourth day of Christmas Cave Johnson gave to me
Four Companion Cubes
Three acid pits
Two testing bots
And an Artificial Intelligence body!
On the fifth day of Christmas Cave Johnson gave to me
NEUROTOXIN.
Four Companion Cubes
Three acid pits
Two testing bots
And an Artificial Intelligence body!
On the sixth day of Christmas Cave Johnson gave to me
Six turrets shooting
NEUROTOXIN.
Four Companion Cubes
Three acid pits
Two testing bots
And an Artificial Intelligence body!
On the seventh day of Christmas Cave Johnson gave to me
Seven mashed potatoes
Six turrets shooting
NEUROTOXIN.
Four Companion Cubes
Three acid pits
Two testing bots
And an Artificial Intelligence body!
On the eighth day of Christmas Cave Johnson gave to me
Eight deadly lasers
Seven mashed potatoes
Six turrets shooting
NEUROTOXIN.
Four Companion Cubes
Three acid pits
Two testing bots
And an Artificial Intelligence body!
On the ninth day of Christmas Cave Johnson gave to me
Nine faith plates launching
Eight deadly lasers
Seven mashed potatoes
Six turrets shooting
NEUROTOXIN.
Four Companion Cubes
Three acid pits
Two testing bots
And an Artificial Intelligence body!
On the tenth day of Christmas Cave Johnson gave to me
Ten subjects failing
Nine faith plates launching
Eight deadly lasers
Seven mashed potatoes
Six turrets shooting
NEUROTOXIN.
Four Companion Cubes
Three acid pits
Two testing bots
And an Artificial Intelligence body!
On the eleventh day of Christmas Cave Johnson gave to me
Eleven thermal ray beams
Ten subjects failing
Nine faith plates launching
Eight deadly lasers
Seven mashed potatoes
Six turrets shooting
NEUROTOXIN.
Four Companion Cubes
Three acid pits
Two testing bots
And an Artificial Intelligence body!
On the twelfth day of Christmas Cave Johnson gave to me
Twelve mashy spike plates
Eleven thermal ray beams
Ten subjects failing
Nine faith plates launching
Eight deadly lasers
Seven mashed potatoes
Six turrets shooting
NEUROTOXIN.
Four Companion Cubes
Three acid pits
Two testing bots
And an Artificial Intelligence body!"
Chell shook her head. And so GLaDOS concluded that Christmas was a silly, pointless holiday. Then she resumed testing.
"Merry Christmas, Chell."