Odds are that the same one or two images come to mind for all of us when we think of days when Sam "wasn't himself." But when challenged to really consider how often Sam had to fight for control of his body, mind and soul, I discovered that Jared Padalecki played an alternate version of Sam Winchester in at least one episode, and often in several episodes, in nearly all 15 seasons of Supernatural. That's a lot of faces for Sam!
What is the best way to do justice to all the versions of Sam we witnessed over the years? We could revisit Sam's journey chronologically. That would recreate the way he experienced his life being hijacked by supernatural forces. It's a bit more interesting, though, to look back at 15 years through the lens of accumulated memories. How many times was he possessed? How many times was he broken down by supernatural powers? All those traumas compounded each other. They could have insidiously perverted who he was as a person, yet, somehow, he chose to forge his trials into a more authentic, stronger, more compassionate Sam. No wonder he inspires so many of us.
So, I've chosen to group Sam's experiences into the categories of forces that overpowered him - both supernatural and human. Let's see how many I found, then you add the ones I've forgotten! Part 1 covers the times when Sam was truly a monster, by all the definitions that matter to a hunter. Parts 2 and 3 study Sam's human failings, both when it was and was not his fault. Parts 4 and 5 looks at Sam when he was supernaturally broken, then Part 6 will cover all the alternate Sams we (and sometimes he!) met through the years!
Possessed Sam
Likely the most well-known of Sam's alter-egos, Sam's possessions dramatically drove Supernatural's plotline for many years. They were all brilliantly portrayed by Jared, as Sam disappeared and another entity altogether emerged in his place.
Meg!Sam - 2.14 "Born Under a Bad Sign"
When Meg was still a terrifying demon loyal to Lucifer, she possessed Sam in a brilliant scheme to infiltrate hunters' ranks and kill them before they could realize that Sam wasn't himself.
I get chills just watching that 2-second replay of a possessed Sam taunting Jo! Within the span of just a few hours, Sam flipped from a cool sociopath, 
to a jeering tormentor, 
to a calculating killer, 
to an enraged demon. 
Dean and Bobby believed in Sam though, so they discovered and expelled the demon before other hunters could exact their revenge for Meg's path of destruction.
Still, this image of a black-eyed Sam is the stuff of nightmares - Sam's nightmares, to be exact.
Samifer - Seasons 5 and 15
Out of all the possible faces for Sam, how many of you thought of this face first?
Hauntingly alluring, we all met Samifer in Dean's vision of the future in 5.04 "The End".
That apocalyptic prophecy scared Dean so deeply, he put aside his doubts and went back to working alongside his brother to defeat Lucifer. 
Sam and Dean did everything they could to prevent Sam from being possessed by Lucifer - but they couldn't stop fate. Months later, in 5.22 "Swan Song", Sam willingly accepted possession in a desperate ploy to avoid becoming the Antichrist who would destroy the world.
(Note that in "Swan Song", Jared recreated the same look of patronizing pity that Samifer displayed in Dean's vision of the future, "The End".)The reality followed the vision, as Lucifer's condescending complacency turned to rage over the brothers' continual interference.
(A cold-hearted Lucifer shows his hatred of Dean.)
It is said that the eyes are the windows to the soul. Possessed!Sam eventually won the battle with Lucifer,
and in a final face of acceptance, cast both of them into Hell. 
To Sam's horror, his triumph wasn't the end of Samifer. In season 15, Sam and Dean were tortured with the recurring nightmare of Sam willingly joining with Lucifer, not to defeat the devil but instead to embrace his supernatural power.
(Ten years after "Swan Song", Jared recreated Samifer in 15.05 "Proverbs 17:3" giving us a view of Sam with the red eyes of Satan.)
It seems Alternate Reality Sams weren't as strong willed or virtuous as our Sam.
(The face of AU Samifer in 15.04 "Atomic Monsters")
Gadreel!Sam (aka Samekiel) - Season 9
9.02 "Devil May Care"
With the best of intentions and after taking every possible precaution, Dean tricked Sam into being possessed by an angel named Ezekiel. At first, this was a match made in Heaven as Ezekiel saved the lives of Sam, Charlie and Castiel.
9.04 "Slumber Party"
But eventually Ezekiel was revealed to be Gadreel, a vulnerable angel who was corrupted by Metatron.
9.09 "Holy Terror"
Gadreel used Sam's body to kill innocents, including Kevin.
9.09 "Holy Terror"
For 8 tumultuous episodes, Dean, Sam and Gadreel battled for agency of Sam's body. Finally, with Crowley's help, Sam prevailed and cast Gadreel out of his mind.
9.10 "Road Trip"
Wicked!Sam - 9.04 "Slumber Party"
Unbelievably, at one point in his life, two different supernatural entities possessed Sam's body at the same time! In the battle of supercharged witch versus recuperating angel versus mere mortal, witchcraft won, and Sam became a puppet for the Wicked Witch of Oz!
9.04 "Slumber Party"
Unless I'm mistaken, Sam was the only character to experience possession by a demon, the devil, an angel and a witch - giving him the personas and faces that glowed with black, red, blue and green eyes! An amazing acting challenge for Jared, and a 15-year horror story for Sam.
Press *Next* to continue with Supernatural!Sam!
