Thrembo is a fictional 'secret integer' that allegedly sits between the numbers 6 and 7, popularized through surreal internet humor and 'gaslighting' posts on platforms like Twitter and 4chan. The meme involves users pretending that this number has always existed and that those who do not recognize it are simply misinformed or part of a collective memory lapse. Often depicted with its own unique symbol—a jagged, stylized squiggle—Thrembo mocks the Mandela Effect and arbitrary internet gatekeeping. It is used to create a sense of 'uncanny valley' in everyday mathematics, forcing viewers to question a reality where the counting sequence they learned in school is incomplete.