The Gospel of John, in its Gnostic form (also known as the Secret Book of John or Apocryphon of John), is an ancient Gnostic text that presents a complex cosmology and a different account of creation and salvation than the canonical New Testament. It is considered highly heretical by traditional Christian churches.
There's the gospel of John also called the secret book of John also called the apocryphan of John which is considered the first most heretical book.
""The 'Gospel of John' is explicitly mentioned, along with its alternative titles 'Secret Book of John' and 'Apocryphon of John', as a highly heretical text from the Nag Hammadi library."