I'm not handicapped. I'm not saddled with a soul. In fact, I used to skipper this meatboat for a while. It was smooth sailing. I was sharp, strong. That is, 'til they crammed your soul back in. Now look at you. Same misty-eyed milksop you always were. That's because souls are weak. They're a liability.
– RoboSam, 6.22 The Man Who Knew Too Much
When Sam came back from Hell his soul was left behind which left him completely emotionless. He had said himself that he didn't feel anything anymore, and had no remorse. The new Sam did anything to kill monsters, even let his own brother be turned into a vampire. Sam claimed that being soulless had a few benefits that allowed him to become a better hunter: He didn't need to sleep or to really eat anymore, he had a higher pain tolerance and was able to lie to the goddess Veritas, even though she could make all other people, even Dean, tell the truth against their will.
This soulless version of Sam had also been proved to be quite dangerous, with his lack of emotion or empathy for others making him something of a sociopath. He didn't seem to care about those he worked with, or even his brother Dean, as he just used those close to him to achieve his own ends. This came to a head by the middle of season six, when Death restored Sam's soul. His next appearances were in flashbacks in 6.13 Unforgiven and in the season finale 6.22 The Man Who Knew Too Much in Sam's head where he was metaphorically killed in order for Sam to regain his memories from when he was soulless.
In 9.17 Mother's Little Helper, the case Sam is investigating in which people are becoming violent and impulsive, reminds him of his year being soulless.
In 11.05 Thin Lizzie, there are multiple references to the year that Sam was soulless. Dean remarks that he was "one chilly droid."
- Robocop was the main character in a movie of the same name about a cop who is wounded and then made into a powerful cyborg.
- Dean also referred to Sam as a replicant in 6.10 Caged Heat, a reference to the cybernetic humans from the movie Blade Runner.
- Other terms used are Soulless!Sam or Not!Sam. General fandom consensus was that RoboSam was very hot and the most badass Sam has ever been.
- RoboSam is shown to be wielding a black handgun, which reflects his soulless nature, as opposed to his regular Taurus Model 92 9mm.