Colbert Bump: While the franchise has been relatively obscure in America for some time (but really big in Japan) outside of Memetic Mutation, the new 2012 anime, as well as its immensely positive reception from many anime reviewers on the Internet, has caused its popularity to skyrocket stateside.
The 2012 anime became one of these for the band Yes, due to usage of their most popular song, Roundabout, as the anime's ending theme song.
Anyone who's played Persona 3 or watched the Persona 4 anime will recognize Lotus Juice, the guy behind much of the soundtrack of Part 2 of the 2012 anime.
Keep Circulating the Tapes: A film adaptation of Phantom Blood came out in theaters in 2007. It hasn't seen any sort of home release. However, an incomplete cut (that is, there is no voice acting, and occasionally full animation is replaced by storyboard stills) of the first 16 minutes has appeared on the internet.
Troubled Production: Apparently, one of the reasons for the poor-quality of the Phantom Blood movie and why it's never been released on DVD was because one of the producers was killed in an accident and his family pulled the plug on funding, leaving an incomplete, rushed mess of a film.
What Could Have Been: Araki originally planned for Part 3 to be a modern retelling of the Dracula story, but most of the Shonen Jump editors found the idea too confusing.
There were plans to release the Vento AureoPS2 game overseas but all of the copyright-problematic Stand names combined with Araki's unwillingness to change any of said names nixed those plans.
Word of Dante: Most fans take for granted that the reboot starting with Steel Ball Run was directly caused by Pucci and Made in Heaven at the end of Stone Ocean. The latter does indeed show an alternate rebooted universe, but neither Word of God nor any applicable in-story confirmation (such as an appearance from Eileen, the reboot's version of Jolyne) have actually shown that Steel Ball Run and JoJolion are set in the same alternate universe.
To be fair, what are the odds of a universal reset followed by a Continuity Reboot in the same series, back-to-back, not being directly connected?
Jorge Joestar tries to explain that the JoJo universe had been resetted so many times, explaining that both the original universe and SBR and Jojolion are still related, somehow... but going into determined stuff in that novel, is the same as explaining that Araki didn't write it, so many explanation pulled in there is non-canonical with the rest of the series, since the book is also like a full compression of fantheories around the series, foreshadowed or not.
JoJo's Bizarre Adventure. It is Exactly What It Says on the Tin. Everything in this series is just mindblowingly bizarre. From the cyborg Nazi guy whose looks inspired Guile, to the timestopping vampire who is also The Casanova, to the vampires who eat other vampires, to the Psychic Powers that can have the most ridiculously specific abilities, to the ridiculous hairstyles and the fabulous clothing. And there's a 16-year-old who has a 30-year-old nephew because his father was in his fifties when he was conceived. No series can top this one when it comes to sheer WTFness.
Let's not even get into where Giorno fits into the Joestar family... note To elaborate, Giorno is Dio's son, conceived after Dio stole Jonathan's body, which makes Jonathan Giorno's biological father. This makes Giorno Joseph's uncle. Note that Joesph is in his eighties by the time Part 5 starts. And Giorno is fifteen. Yeah.
By sheer nature of his never having been human, no villain can top Kars for WTFness. (Except perhaps an out-of-it Pucci in one particular chapter.) Of course this also applies to just about any other series as well. The stuff he could do, simply unreal!
But the most bizarre thing is the mangaka himself — he hasn't aged a day in over 20 years (either that, or he's aging backwards). Recent photographs show him looking younger than he did when he started on Phantom Blood...back in 1986.
Araki has a big thing for Classic Rock. The sheer number of references in his work is baffling. Even the series name is a Shout-Out to The Beatles song "Get Back". This was a nightmare regarding translation, since most of the names were copyrighted, so they had to rename a lot.
And as it went on, a little pop group here, a little rapper there, in addition to more contemporary bands.
Tying in somewhat to the first bit of trivia, was the very first scene depicted. The story actually started before Jonathan's time, back at least two millennia in some South American civilization, which eventually died out for one reason or another, had used the Stone Mask to gain immortality as a vampire. And the first character shown was a maiden to be sacrificed. Eesh.
Which is Retconed when it is revealed the Pillar Men, specifically Kars, created the Mask.