I'm a pretty skeptic person who likes evidence and scientific fact over conspiracy theories...however interesting they may be. There is a far more simple explanation than an alternate universe: the brain is just filling in missing details and easily influenced by the power of suggestion. It's just psychology.
Our brains don't retain ALL information. It will catalog enough information to get the point across. For example, we don't necessarily read every single letter in a word. The brain recognizes words -- not letters -- which makes for faster and more efficient reading. If the first and last letters are in the right place, the letters in the middle can be mixed up but you'll still be able to read it fairly quickly. There have been memes about it running around facebook for years:
Likewise, when we are trying to remember something, our brain will fill in the blanks. This is also why eyewitness testimony is often unreliable. Three people can witness the same event, but give very different details of what they saw. It isn't that they're being dishonest, it's just that their brain remembers the "big picture" of the event and when asked about details, it is generally not photographic recall. For example, we may clearly remember seeing a man snatch a woman's purse on the street...but what clothes the man is wearing -- and especially the color of those clothes -- may not be information that our brain actually retains from the brief encounter. When you "look back" in your mind, the picture you see may be accurate, or your brain may have essentially "colored" the picture for you or drew in missing pieces based on information that is already stored...like the assumption that someone was wearing clothes in public, pants are often jeans, details from people our brain has seen before, etc.
I mean...we already know that our brain has the capacity to do this. Our dreams come from sources we've already encountered. You can "picture" something in your mind just from a verbal description. If I say "dinosaur" then your mind can imagine a dinosaur if you've ever seen a picture of a dinosaur before to reference from. Or maybe you've never seen what a pterodactyl actually looks like. However, if you've seen a bat and a pelican before...I could tell you that it looks like a really big bat with a face that looks like a pelican. While you may not "see" it exactly, you may be able to piece those things together to get a general idea...based on information your brain has already stored.
So...your brain filling in blanks with information it already has and trying to recall details from suggestions is really the explanation behind the Mandela Effect. I found this link with 40 examples the Mandela Effect. They explain how a few of them might be confused with something else. Here are some more possible explanations...
1. Nelson Mandela dying - Of course this is the first one, since he inspired the theory. Mandela was imprisoned for almost 30 years before being released and then later becoming the first post-Apartheid president of South Africa. People claim to remember him dying in prison. Well...nearly 30 years is a long time to be removed from society. People say they remember news reports of his death and a televised funeral. Well...your brain knows that a funeral often follows a death and that famous people are covered in the news and there have been televised funerals before. Your brain can remember ANY televised funeral and associate it with someone else. People have also said they remember riots following his death. Well...there were riots the day Mandela was released from prison in 1990. So the memory of the riots occurring is true...it just wasn't because of his death. And if someone asks you, "Do you remember Mandela dying in prison in the 80s?" That right there is a suggestion that he died...so your brain may take that suggestion and the pieces of things you may remember about Mandela and fill in the blanks under the assumption that he died. So your brain may spit out that Mandela was gone for a really long time, a televised funeral for someone famous and the news coverage of riots related to Mandela and then suddenly you "remember" that he died in prison...even though he didn't.
2. JIF peanut butter remembered as JIFFY - There is a "Skippy" peanut butter...but there's also "Jiffy" bakery mixes (like Jiffy corn muffin mix). Now mix that with the suggestion that someone else remember's it as Jiffy peanut butter and you're "remembering" a peanut butter brand that doesn't exist...especially if you don't actually eat that brand of peanut butter. My dad has always bought the huge size Jif extra crunchy peanut butter...so my brain has retained the details of that information because I'd bought it for him before.
3. Looney Tunes remembered as Looney Toons - One would assume it is "toons" because it is a cartoon. However, when Looney Tunes was created, they were just short black and white animations with no dialogue...it only featured the music with the animations and thus the reason for "tunes" (which basically means music). Even the characters typically associated with Looney Tunes (like Bugs Bunny, Tweety, Taz, etc.) didn't appear until about a decade after it's creation. That memory is also influenced by the later creation of "Tiny Toon Adventures" which features some of the characters later created in Looney Tunes when they were younger.
4. Berenstein Bears instead of Berenstain Bears - People swear that the popular book used to be Berenstein Bears instead of Berenstain Bears. Frankly...it's just a matter of assumptions. There are a lot of surnames that have more or less common spellings with the change of just one letter: Henrickson instead of Hendrickson, Thomson instead of Thompson, Dorion instead of Dorian, etc. And it goes back to the brain just assuming the letters in the middle of words based on what we know.
5. Curious George with a tail instead of without - This one is very simple. We know monkeys have tails, so we assume because he is called the "little monkey" that he should have a tail. Well...he looks like a chimpanzee which is an ape...and they do not have tails (they are also found in Africa which is where Curious George came from). And monkey used to be more of an "umbrella term" for any primate that wasn't a human.
6. Sex in the City instead of Sex and the City - It's always been Sex and the City which comes from the name of the column that the character Carrie Bradshaw writes. It is common for "n" to be used in place of "and" which sounds just like "in" when it is spoken. So people hear "Sex 'n the City" and make the assumption that the title is Sex in the City instead of Sex and the City...especially since they were having a lot of sex in the city. :P It's just a common mistake.
7. Febreeze instead of Febreze - This is just an assumption our brains make based on the face that "breeze" is a common word...but brands often choose to have unique spellings. That is the case here.
8. Remembering Oscar Meyer instead of Oscar Mayer - Again...it is an assumption based on common spellings that we are familiar with. The jingle from the commercials "My bologna has a first name, it's OSCAR..." always said MAYER. It was named after the German American founder...whose name was Oscar Mayer.
9. Sketchers instead of Skechers - Again, this is an assumption because "sketch" is a common word that our brain recognizes but the brand spelling is different.
10. Fruit Loops instead of Froot Loops - Same thing..."fruit" is a common word but the brand chose to spell it differently...which in this case was to be similar to the second word "loop."
Those are the first 10. I'm not going to do all 40 of them because I'm already taking up a lot of time on this subject. :P But number 27 is what inspired this blog post in the first place. It's the one about "We are the Champions." It states that Freddie Mercury does not say "Of the world!" at the end of the song. And that's true...he doesn't say that at the end of the song. However, the key part of that statement is "at the end." If so many people were just imagining the completely made-up lyrics "of the world" that would really be impressive. However, the lyrics "we are the champions of the world" does appear in the song. So your brain already knows those lyrics...it just makes the assumption that it's the same throughout the song...despite the fact that the last line of the *original* song is just "we are the champions" without the rest of the line.
So...I just think there are far more logical explanations for these false memories than the idea that there are parallel universes which change ridiculously mundane things like "Berenstain Bears." :P I mean...what would be the point in changing spellings in alternate universes? Does it *really* matter that much? :P What do you think?