The cartoon shown at the ending of "The Cartoon" has a two fold example. It's partly a mystery cartoon , hence why Frank Welker voices the narrator. We also have Jason Ritter voicing an awkward and intelligent young boy, Kristen Schaal voicing a young excitable girl, and Alex Hirsch voicing both a cool, laid back dog and a grumpy but nice old man. Where did the crew get that idea?
Word of God states that the show was going to have a continuity and more complex stories told in 22-minutes long episodes, but Disney XD wanted a 11-minutes long gag series.
Even more so, Craig wanted the third season to have a lot more story lines and more developed backstory, but Disney canned the series because "80 episodes were enough".note And the implications of this phrase just seems to make it worse. In Frank Angones' FAQ post about the cancellation, he speculates that what that phrase meant was that the execs noticed that Wander did a lot better ratings-wise in reruns than during premieres, and that "80 episodes was enough" because they could cut costs by constantly re-airing the series instead of paying for new episodes.
Flip-Flop of God: The show's crew like to keep in touch with the fanbase through tumblr, and often answers questions they might have. However, often times, different crew members may give different answers for the same question, leading to some confusion. One notable example is the question of whether or not Lil' Bits is an actual evil kitten or an adult posing as a kitten.
I Knew It!: The stinger for the series finale strongly implies that Lord Hater is a NASA space chimp who was revived and uplifted by dark magic after drifting into the show's galaxy. This was a fairly popular fan theory about his backstory after "The Waste Of Time" had a Freeze-Frame Bonus showing a space chimp that had a facial structure suspiciously similar to Hater's.
Many fans also predicted that Wander would fail to redeem Lord Dominator. Sure enough in the series finale that's exactly what happens, though to be fair, it's likely the show was meant to continue that arc in a third season
Official Fan-Submitted Content: Many of the names of the villains on the Galactic Villain Leaderboard, kept track of by story editor Frank Angones on his blog) are original characters created by fans.
The show didn't get its 3rd season, not because of low ratings, but because higher-ups decided that 80 episodes (over 3 years) was enough for one series. What made this baffling is that said higher-ups were willing to wait for Alex Hirsch to see if he would change his mind on doing one more season of Gravity Falls (to which he declined and ended the series after two seasons after 4 years) but wasn't willing to give the same courtesy to Craig despite both shows being top-rated of the network. Most suspect it was cast aside to make way for the newer toons incoming on the channel at the time (namely the Ducktales reboot, Marvel's Spider-Man and the Big Hero 6 TV series note Notable all brand names) as a cost saving measure.
The channel jump from Disney Channel to Disney XD didn't help matters either. Not everyone has XD, and Wander was barely advertised on Disney Channel once it made the jump; anyone would think Disney has had it out for this show since the beginning.
What's more, not long after the show ended. It was pulled from rotation on the network and not rerun at allnote Running said reruns was the supposed reason why it didn't get renewed in the first place. The commercial bumps (the ones with Hater trying to threaten Wander) still play occasionally, but at the current, that's generally the only remains of the show. The only times it returned to the network was for its Christmas Episode (The Gift 2 and The Gift) in December 2016, and a 10PM to 6AM season 2 marathon on June 25th, 2017.
Sending Stuff to Save the Show: Almost immediately after the staff announced that the second season would be the last, a "Save Wander over Yonder" fan campaign started gaining ground, and people started emailing Disney for a third season.
Short Run in Peru: France got "The Hero/The Birthday Boy" a few days before the US did. Latin America also got a handful of episodes the weekend before their US airings too. More infamously, The Netherlands got "The Liar/The Stray" first.
Hater's origin story was also confirmed for Season 3. Apart from some foreshadowing in the credits animatic of the series finale, nothing more will become of it.
Speaking of which, the crew have relentlessly teased fans on tumblr regarding what they had in store for Season 3.
Hater's backstory would have been revealed in Season 3.
The Galaxy will face a new threat, one even MORE dangerous than Dominator.
Said threat will most likely not be a new villain.
Three new main characters would have been added, similar to how Dominator was added in Season 2.
Peepers would have been tempted by the dark(er) side.
Season 3 would have been about testing Wander, in the way that Season 2 was about testing Hater
The backstory for how Wander and Sylvia met was much different. Back when the show was conceived to be serialized, Zbornaks were something of steeds crossed with cabbies(Hence Sylvia's saddles). Wander caught a ride with Sylvia, but couldn't make the fare. So the two traveled over the course of season one with Wander almost getting paid for helping each episode. This would culminate into Sylvia growing to love Wander and adopt his attitude, making her more of the protagonist of season 1.
Word of Gay: The show's writers have confirmed that Emperor Awesome is pansexual and Sourdough the Evil Sandwich is genderfluid. Everyone else's gender identities and sexual orientations, however, are open to fan interpretation.
Word of God: The crew keep in very close touch with the fandom over tumblr, often dropping hints and trivia regarding episodes of the show. (See above)
In "The Battle Royale", McCracken said Something the So-and-So's long-winded talk was added because the episode was too short and they needed more time.