Wheatley

"I can't get over how small you are! But I'm huge! (Maniacal laugh) ... Actually, why do we have to leave right now?"

- Wheatley becomes the villain "Well, this is the part where he kills us"

- GLaDOS "Hello, this is the part where I kill you."

- Wheatley

Wheatley is the tritagonist turned main antagonist in Portal 2. He is voiced by Stephen Merchant.

History
At the beginning of the game, Wheatley awakens Chell, who has been in stasis for several years, and tries to help her escape the Aperture Science facility, but is supposedly destroyed by GLaDOS when she is accidentally reactivated. However, he appears in hidden areas of the facility to Chell, and later helps her defeat GLaDOS by replacing her program in the main control system with himself.

But right when Wheatley is about to let Chell go free, he becomes corrupted and betrays her, accusing Chell for selfishly using him. He traps GLaDOS in a potato battery, and she recognizes his voice as a program the scientists once installed into her that gave her terrible ideas in an attempt to slow down her rise to power. Infuriated, Wheatley breaks the escape platform and throws them both into an extremely deep shaft leading to the lowest areas of the facility. As they fall, GLaDOS explains that Wheatley was designed by the scientists to always come up with bad ideas (in her own words, to be a "moron").

When Chell makes her way back to the main facility with GLaDOS, Wheatley has redesigned all the test chambers in his own image, combining the turrets and companion cubes into one and even changing the logo on the loading screen to "Wheatley Laboratories". However, as he is designed to make bad decisions, he has neglected to maintain the lab's failing systems, putting the facility at risk of a nuclear meltdown. When they encounter him on a screen, GLaDOS tries to stump Wheatley by saying a paradoxical statement ("This sentence is false"), but Wheatley ignores the error and goes with "true". Eventually they reach the main chamber again, where Wheatley states the facility is about to explode and he has been studying the final boss fight from the first game and has changed all the things that allowed GLaDOS to be defeated then. Despite this, Chell is still able to corrupt and replace his personality cores. She is about to press a button that will replace his program with GLaDOS when Wheatley reveals that he had booby-trapped the button and it explodes, injuring Chell. The facility is about to explode, causing panels to malfunction and disappear, like one which reveals the Moon in the sky. Chell shoots a portal up to the moon which sucks everything onto its surface, including herself. GLaDOS reaches out to get Wheatley out of Chell's hands and then she pulls Chell back inside.

After the credits, Wheatley is seen floating in space along with one of his personality cores, who is obsessed with space, where he laments his fate and says that he feels genuinely sorry for betraying Chell and wishing to have the chance to apologize to her.

Wheatley appears again in Team Fortress 2 as a Sapper for Spies. (Ap-Sap)

Wheatley is set to appear in a Portal 2 campaign in LEGO Dimensions.