T-5000

Alex, the T-5000, is the hidden secondary antagonist of the 2015 sci-fi action movie Terminator: Genisys.

He is portrayed by Matthew Smith, who also portrays The Doctor in TV Show Doctor Who Series 5.

Terminator Genisys
At a certain point, Skynet uploaded itself into a T-5000 Terminator and infiltrated John Connor's Tech-Com unit, leaving its core in Colorado as a decoy.

Alex then participated in Operation Chrono; after the control center in Colorado was destroyed, Alex attacked John Connor in the Time Displacement Chamber when Connor was seeing Kyle Reese off. While turning John Connor into a T-3000 Infiltrator, Alex revealed he was Skynet itself and killed the other Tech-Com members who were present.

In 2017, when the Genisys Program started becoming whole, Alex's image is used as one of the the holograms to represent Skynet itself in Cyberdyne Systems Headquarters.