Kellogg's cheesy snack

Here's another branding curiosity.

Since 1921, many people have enjoyed the famous Kelloggs snack crackers thinking they were called "Cheeze-Itz", and are surprised to find today they've been using the wrong name all along. Despite it having the "Cheeze-It" name for close on 100 years, it still comes as a shock when they see the big lettering on the pack which plainly says "Cheeze-It".

There is a class of spelling Mandela Effects where the pronunciation is the same for all variants, and an even subtler class where the plural is assumed to be the real name because it is naturally spoken out loud more often. Examples are Depends underwear and Braggs. With this one, the "z" always appears in the first word, so appending it to make the plural seems a good fit for stylish reasons.

Green & Green

They first appeared in 1921 when the Green & Green company of Dayton, Ohio launched them with the tagline "A Baked Rarebit". Through several buyouts, the brand was eventually acquired by Kelloggs in 2001. In 1929, during the Wall St crash, people even stocked up on it fearing widespread food shortages. Like Coca-Cola and KFC, the actual recipe was a fiercely guarded secret, but all that changed in 1986 when the mystery surrounding how they tasted so cheesey was revealed to be  ... real cheese!

The way the product name is used is almost always plural, as in "I'm going to get some Cheeze-Its", because in most cases the singular just wouldn't make sense, even when trying to be correct. An example is "I'm going to buy a pack of Cheeze-It", which, whilst grammatically correct, still just doesn't sounds right to most people so that's not what they say instinctively. Although, in this case when converting to the plural a regular "s" would probably be used rather than the stylized "z".