What is Arthur the version of Harry Potter called?

There's no version of Harry Potter called "Arthur." The name "Arthur" is most likely a reference to:

* King Arthur: A legendary British king featured in Arthurian legends.

* Arthur Weasley: A character in the Harry Potter series, who is the father of Ron Weasley and a close friend of Harry's.

It's possible you're thinking of something else entirely. Can you provide more context or details about what you're looking for?