Throughout the series, each of the main characters spots their own lookalike out in the world. But none of the doppelgangers is quite like the original. Some fans speculate that each doppelganger actually represents the true desire of the character they resemble. There's lesbian Robin, stripper Lily, mustache Marshall, Mexican wrestler Ted, and fertility specialist Barney.
Reddit user MiserableThinBelgain broke it down, describing the desire each doppelganger was depicting:
- Lesbian Robin is the masculine version of Robin that her father desired. A part of Robin likely wishes she could have remained masculine.
- Mustache Marshall is not only a lawyer but grows a sick mustache that Marshall can never grow. And for Marshall, who wasn't even in law school yet when he saw him, this is very desirable.
- Stripper Lily represents the part of Lily who wants to embrace her slutty side and not have to worry about being a mom or being responsible.
- Mexican Wrestler Ted is this macho cool version of Ted who his friends adore because he doesn't go on long rants. And he fights robots.
- Fertility Specialist Barney gets to look at women's vaginas all day.
Reddit user SpamFilterHatesMe shared "A Study in Violet”, a theory that points out the strange re-occurrence of purple in the show. For instance, the entire cast wore purple in season seven’s “No Pressure,” the episode where Ted and Robin end their pursuit of each other. The episode ends with yellow umbrellas, which are a symbolization of the mother.
According to basic art theory, the opposite of violet/purple is yellow, therefore the pursuit of Robin is preventing Ted from finding the future mother of his kids. He has to move on from purple to yellow to find her. Another redditor hilariously pointed out that Barney, who marries Robin, shares a name with a purple dinosaur.
Tumblr user gingersaurus believes Barney is actually a way better person than he's made out to be. According to this fan theory, the show's playboy is actually much less obnoxious. The fan points out that Ted narrates the show and wants to be with Robin.
He also wants his kids to accept his decision to be with Robin. Convincing them Barney is smarmy and undeserving makes Ted seem like a good guy for "saving" Robin from Barney's clutches.
Spoiler: In the show, Barney has a one night stand with a random woman, and ends up becoming a father. Seems pretty straightforward, but some fans don't think that's the whole story. In fact, according to one theory, Barney didn't have the baby by accident at all. Instead, he actively sought out an adoption so he could have kids.
The theory assumes that Barney (like Robin) is infertile. How else could he have slept with so many women without getting anyone pregnant? But unlike Robin, he realized he wanted kids, but couldn't admit it to his friends. To keep up his playboy persona, he pretended to go out with women every night, while actually researching adoption agencies and trying to find the right match.
When he finally does, he claims the baby is a result of a one night stand instead. Since it's a closed adoption, he can never reveal the true identity of "Number 31," his kid's mom.
Check the theory in its entirety, re-shared by KyoryuRed from a now deleted Tumblr post.