Ogg is also a character in the Harry Potter book series by J. K. Rowling.

According to Molly Weasley (Ron Weasley's mother), Ogg was the keeper of the keys and grounds at Hogwarts school for witchcraft and wizardry before Rubeus Hagrid. She says he was there when she was a student.

But this brings to a problem! Hagrid became the helper of the keeper of keys on 1942/1943 (not certain), and several years later became keeper of the keys himself.

If so, Molly should have finished Hogwarts (at the age of 17) before 1942. But Molly has a child who was born in 1981 (Ginny)!!!

Very confusing indeed...