Back in the pilot episode of Westworld, no one could have predicted that Peter Abernathy would become as important as he is. He was one of the first hosts to malfunction, but he was quickly put away in cold storage; episodes later, he came back into play when Charlotte Hale needed a host to sneak a vast amount of information out of the park. Season 2 has seen multiple characters on the hunt for him, which resulted in some Peter Abernathy Westworld theories from fans that could change how you look at the character.
Since it came as such a surprise when Peter re-entered the narrative at the end of Season 1, viewers are prepared for his arc to go anywhere in the future. He's already moved far beyond his role as a glitching host foreshadowing what was to come; now not only does he hold the key to Delos' future developments, but he's proof of how humans have mistreated the hosts time and time again. Their constant fiddling with his mind left his identity in flux, his memories destroyed. His story could go in almost any direction now, and these theories prove that the audience is primed for any possibility.
Peter's Secret Identity
Reddit user Gunslinger1969 put forth a theory that has quickly become rather popular: Peter Abernathy isn't Peter Abernathy at all. He's actually James Delos. Wait, what? This idea posits that when James was dying, he somehow had his company download his consciousness into a host body — specifically, Peter's. That was why the picture of Juliet caused Peter to malfunction in Episode 1; seeing his daughter unlocked something in him. Unfortunately, this theory doesn't really explain why they'd give James multiple new identities (first the Professor, then Peter) and keep him in the park for decades. Just for fun? To be honest, I wouldn't put that past Robert Ford.
Another common theory is that Bernard foiled Charlotte's scheme somehow in Episode 3 when he was de-encrypting the file she left in Peter's mind. Several Redditors, sidewalkchalked included, speculated that Bernard uploaded the file to his own mind instead. He then became in control of the information, but it also left him jumbled and glitching in the two-weeks-later timeline. Bernard was acting suspiciously Peter-like when fans caught up with him on the beach; if he didn't want Delos to get their hands on the file, it could make sense.
Bait & Switch
This theory follows on the heels of the last. Reddit user sixthK5 is on board with the idea that Bernard transferred the file from Peter to himself, but then went on to theorize a scene from the trailer could play into Bernard's larger plan. There was a shot that showed Charlotte standing with multiple Bernard bodies. The Redditor wondered: "So I was thinking that maybe the hosts will come up with a plan that involves using the Bernard's bodies (which I think were shown in a trailer?) and upload their 'characters' to them so Delos won't know in which Bernard the info is."
But they couldn't imagine why the hosts would want to protect the file so badly.
Oh My Darling Clementine
Another thread on Reddit wondered why Peter and Clementine were acting so differently when they'd undergone the same lobotomizing procedure before being put in cold storage. Clementine was essentially a zombie, while Peter was acting similarly to how he did in the pilot. It was determined by multiple users that Charlotte and Sizemore's intervention left Peter with a shell of a personality, but it also raises an interesting possibility. Perhaps the hosts aren't totally destroyed after the drill procedure, but instead can be returned to some semblance of consciousness. Like Peter, Clementine could have her personality partially rebuilt.
Secrets In The Code
An article on Heavy noted that there was a strange, almost honeycomb-like symbol in Peter's file that was also present in Grace's notebook in Raj World, as well as the station where Charlotte and Bernard took refuge in the Season 2 premiere. There must be some kind of connection there, though it's impossible to say what it is when there's just a single image to go off of. Maybe Charlotte (and Grace too) are working with another company that uses that symbol. Perhaps the file wasn't for Delos at all; it was for someone else.
Peter has been McGuffin pushing along a portion of the plot in Season 2, but Bernard's decision to unlock the file might have changed everything. Redditor gotdemmadsquirtsyo pointed out that there was a one time use key on the file, which could mean Peter is no longer usable by Delos standards. Maybe the information can no longer be accessed by him at all, ruining Charlotte's plan and taking Peter out of the action almost as quickly as he joined it.
Peter will almost definitely continue to have a presence in Season 2, but there are many different paths his story might follow. Fans will just have to wait and see.