WMG / Bakemonogatari

Karen is also some kind of supernatural creature, or at least partly touched by the supernatural
It's hard to otherwise explain her phenomenal physical strength - no other human character in the series exhibits anything remotely close to it without using magic or getting aid from a supernatural being. Given that her brother is a vampire and her sister is a phoenix without even knowing it, it wouldn't be all that much of a stretch.

Psychologists are specialists who deal with apparitions
Apparitions have a hand in mental illness, and people's personal problems like in the case of Hitagi, Tsubasa, and Nadeko. Psychologists unknowingly deals with these apparitions. In the Monogatari universe specialists probably are psychologists, most of them concealing the paranormal aspects of their job from the general public.

Gaen is omniscient
How could she know everything? How could she know about the "darkness" or the newer types of apparitions such as Hanekawa's Kako and the fact that Ougi Oshino is some kind of dark version of Koyomi. In moments she claimed to be suprised, she might be just bluffing.

Or she might be just a good mind-reader whether figuratively from subtle social cues and gestures of characters around her, or can literally read everyone's mind. Though she is careful not to say anything that might give a hint to other characters that she can read minds.

Ougi Oshino is not Meme's niece as she claims
As stated by Kaiki to Hanekawa, Meme has no relatives.
  • But Kaiki may just be lying to Hanekawa or that Meme thought all his relatives were dead.
    • Confirmed. Ougi is an apparition created by Koyomi

Hanekawa does not plan to go to college because...
She plans on becoming a specialist. That's why she is travelling around the world to get first hand experience with various apparitions.

Tadatsuru is cursed of knowing how everything would play out in the future
How does one explain how he seems to be expecting his meeting with Koyomi but doesn't seem to have forsaw his death through the hands of Yotsugi.

  • Possibly Jossed. It was revealed in hell that it was part of a plan with Gaen in an elaborate plan to thwart Ougi. He got information from Gaen, who is possibly omniscient. That is why he was not surprised by his "death".

About the apparition involving Tsukihi...
Tsukihi has supernatural regeneration due to her being an offspring of the Shide no Tori. When Koyomi learned the fact that her sister is an apparition, he is conflicted whether to reveal the truth to Tsukihi. Ougi has taunted that Tsukihi has no future at all suggesting that the lifespan of a Shide no Tori ends shortly after Tsukihi graduates from college or even earlier. However this may be reflecting Koyomi's uncertainty regarding Tsukihi's nature, since Ougi IS Koyomi and only knows what he knows.

In a later arc possibly before Hanamonogatari or after it, Koyomi will deal with this apparition. Tsukihi may be wounded so much that her regeneration isn't enough that she may take the phoenix form of the Shide no Tori and finds a new host to be reborn. Or maybe this would result to Tsukihi discovering her abilities as an apparition and may lived to enjoy a normal human life after all.

Sodachi will deal with an apparition
She is the only whose personal problems didn't revolve around an apparition. However she might deal with one in future arcs.

Impossible crossovers

Okay, honestly, I only started thinking this because I noticed Takahiro Sakurai voices both, but it's not that out there, is it? It's been noted that both shows have similar formats and concepts.

The Medicine Seller is immortal, and if he is a mononoke like on Mononoke's WMG, who says he can't shapeshift? He didn't bother back in the 1920s because while his outfit was rather out of place, there were still people running around in kimono back then, so nobody made a huge deal out of it. Nowadays everybody would call him out on it, so he traded in the ridiculous kimono for a ridiculous Aloha shirt. As for whatever happened to his sword...perhaps it became corrupt some way or another and became Heart-under-blade/Shinobu, who has occasional access to an absurdly sharp sword.

Shinobu is/was a one of the 27 Dead Apostles
Well, she was a vampire. And in the first episode, during the Fake-Out Opening I swear, there was a priest and a few other things. I haven't read the light novel, but maybe an attempt to seal her by a burial agent? As for Araragi, his case was like Satsuki, where he was one of the 1 in 10,000 able to become a vampire and also able to skip the first two steps.
  • Type-Moon vampirism is permanent.
  • Indeed it is, but nothing is impossible for the Medicine Seller (see above).

Oshino somehow knows Yuuko.
For one, they both deal with the supernatural. Two, Yuuko seems like his Distaff Counterpart. Three, they both have a Watanuki-like figure (i.ie, an adorkable teenage boy whom they love to tease. Lastly, they both disappear at some point, leaving their little teenage boys alone to fend for themselves... sort of. What this troper wonders most is why he hasn't written a crossover of xxxHOLiC and Bakemonogatari.

Apparitions are the forms that mushi take in the modern world.
Following WWII and the surge of Western values into Japan, people began to no longer accept the existence of mushi. As a result, they turned into becoming things far more supernatural than animalistic in nature. This means that Oshino is one of the few mushishi still doing that job; as we can see, it's probably not very profitable so few do the job anymore. This is not even taking into account Koyomi's similar appearance and personality to Ginko.

"You can't hate an animal for doing what nature made it to do."
-Ginko
"It's wrong to pin blame on an apparition, because they simply are what they are. That's all there is to it."
-Koyomi Araragi

Witches in Puella Magi Madoka Magica are apparitions.
Which are created by the magical girls themselves. In a manner similar to Kanbaru's mother subconsciously gave birth to the Rainy Devil or Koyomi creating Ougi Oshino. Instead they become the apparition themselves, a fact withheld by Kyubey.

Simillarly Walpurgisnacht is an apparition created due to the spread of a rumor of the witch coming to Mitakahara in a certain date and not from a individual strong magical girl falling to despair.

Alternatively, the Monogatari Series is a sequel to Puella Magi Madoka Magica.
The universe was recreated where Magical Girls don't exist anymore meaning no girls can't become witches. Traditional witches probably still exists in the Monogatari series as a type of apparition. Instead of the Magical Girl system by Kyubey's race being the prime cause of advancement of the human civilization, apparitions are somehow involved in this.

The Big Bad from Barkley, Shut Up and Jam: Gaiden is an apparition
Shadow Barkley is an apparition. As stated in the game he was created back in Space Jam and is the embodiement of the negative thoughts of Charles Barkley. It represent's Barkley's desire for everyone to enjoy basketball. The worldwide ban of basketball did everything worse and just made the Big Bad's powers stronger.

Dracula, Bigfoot, and the Lochness Monster exists in the Monogatari universe
It has been stated in the series that apparitions are born from superstitions so Dracula, Bigfoot, the Lochness Monster and all other supernatural beings or cryptids exist in the Monogatari universe.

Slenderman is an apparition
Slenderman is an apparition created due to the spread of creepypasta about the faceless being. In connection to the previous WMG, some apparitions in the Monogatari series are probably created by creepypasta.

The Green Goblin is Norman Osborn's apparation
it was created after Norman Osborn experimented on himself. The Green Goblin is an apparition which embodies Osborn's suppressed misanthropy. Like the Rainy Devil, the Green Goblin also helps Osborn do what he could not do himself like kill the board members of Oscorp who planned to oust him
http://tvtropes.org/pmwiki/pmwiki.php/WMG/BakeMonogatari