I just learned about it today—basically it's an effect where a large group of people remember something that didn't actually happen.  For instance: 
I remember KitKat having a dash.
I remember Berenstain Bears spelled Berenstein Bears
Oscar Mayer was Oscar Meyer.
The Mandela effect is cool but freaky tbh.
			
			I remember KitKat having a dash.
I remember Berenstain Bears spelled Berenstein Bears
Oscar Mayer was Oscar Meyer.
The Mandela effect is cool but freaky tbh.