Basically, a headcanon is something you consider canon in your head, but has not been officially proved or disproven. So lets start:

Spaz has a voracious appetite and will eat just about anything.

Spazzes girlfriend is actually not Lori. I know she was originally meant to be, however I will keep thinking this way because it fixes the plothole, and the prototype looks different enough from her. The only thing thats the same is the colour scheme.

Lori is actually a half sibling.

So, do you have any headcanons?

The turtle who pulled Jazz aside in the JJ1 comic to brief him on Devan later became Dark Shell.

I've been a fan of Jazz since the second game came out, so I've thought about this for years. And, when you consider the fact that the Jazz canon is pretty bare bones after Jazz 1, my headcanon is very in-depth...

The entirety of JJA was a drug-induced dream that was actually a failed assassination attempt(Kind of like the Matrix meets Inception, except heavily inspired by Star Wars and set inside Jazz's mind). The villain who set this all up is the turtle from the JJ1 comic, who put himself in the dream and became Dark Shell. After the dream, Jazz imprisons the turtle and uses information from him to track down Devan. So then, after a while, Jazz cryogenically freezes Devan(Since he would break out of prison, and killing him would make him a martyr, and plus he might be useful in the future). So then, Jazz spends most of the rest of his life as a family man ruling Carrotus.

There is more, but what I've put above only about half of Jazz's story(Less if you count details I skipped/skimmed over), and then there's Spaz, Lori, and the rest of Devan, so we're talking walls of text here(Maybe I'll post something in the War Tavern at some point).

The Jungle levels were an area in Hell too.

Hah well, I have a little backstory err...headcanon of Lori, though I wanted to save it for the SP project I had in mind. But it's not like I ever finish levels, even moreso not a group of them so I'll probably just post it anyway.

Originally Posted by cooba

The Jungle levels were an area in Hell too.

Something crazier:

One must travel to ancient past of Carrotus to enter hell because in its young age, the planet has a gaping, easily accessible portal to it. The in-game jungle levels are so dangerous because they're in close proximity of the portal and evil is leaking out (as indicated by creepy eyes in walls).

Also:

Devan was given the ability to transform into a demon by Bubba, the penultimate boss, for creepy reasons.

Bolly is an abandoned, unmanned model of the very first boss in JJ1.

Chuck is a one-of-a-kind hip-hop, and a hero amongst his race, for his ability to defeat enemies bare-hands... I mean, bare-wings.

The Flashbacks (JJ2) episode takes place at the exact same time as the Turtle Terror (JJ1) episode. You never meet younger Jazz because they're in different locations of the planets (hence the visual difference).

Psych isn't a time period, but a dimension between times. The long-unavailable Rotate background was to emphasize this.

There is a stable timeloop created by the events of JJ2. Because Devan went back in time and attacked Carrotus centuries ago, the Galactic Rabbits fought an uneven battle (well, uneven if it weren't for Jazz & Spaz) and their civilization's advancement was slowed. They did, however, advance unnaturally in militaristic fields. This is why in Jazz's time, royalty lives in an old-fashioned castle surrounded by far-reaching fields untainted with urbanization, BUT at the same time they have weapons compatible with Turtles' ammunition. Devan himself unknowingly made his nemesis a threat.

I had more but that's all I can remember right now.

Originally Posted by DoubleGJ

There is a stable timeloop created by the events of JJ2. Because Devan went back in time and attacked Carrotus centuries ago, the Galactic Rabbits fought an uneven battle (well, uneven if it weren't for Jazz & Spaz) and their civilization's advancement was slowed. They did, however, advance unnaturally in militaristic fields. This is why in Jazz's time, royalty lives in an old-fashioned castle surrounded by far-reaching fields untainted with urbanization, BUT at the same time they have weapons compatible with Turtles' ammunition. Devan himself unknowingly made his nemesis a threat.