I couldn't help but join the conversation on this one. Here we go...
I think others have done pretty good work on the fictional cosmology here. Cool World and our world are part of a multiverse with different levels of chaos/malleability. Our world is pretty solid, while CW is much looser and more easily influenced by visitors (hence the power of ink). Sometimes people from this world can cross over into other worlds in moments of extreme emotion. Mostly they write it off as dreams or visions. Harris visited in a moment of trauma and just flat-out stayed (I'll get back to that in a second), while Jack visited in reaction to his own self-inflicted trauma and turned it into a successful comic book from prison. The stuff with Doc Whiskers and the Spike are pretty well explained elsewhere in this forum.
So I'll jump to theme. The movie Cool World is about dangerous imagination. Harris is unique in that he displays practically no imagination. He's Officer Friday crossed with Spock. His retreat into Cool World makes him an anomaly there, a force of rational order in a world of chaotic imagination. So of course he becomes a cop - it's a metaphorical way (which is how CW operates, really) to reconcile his presence there. Harris is also kind of the early 20th century response to dangerous imagination - keep it under wraps and regulated and absolutely NO SEX (think the Hays Code or the CCA).
That brings us to Jack. He taps directly into messy, chaotic CW and instead of trying to control it, he turns it loose in the form of a prison comic. He's kind of a stand-in for Bakshi and Crumb and those underground comix guys that shrugged at codes and rules and went wherever their imagination took them, usually into a more extreme place like CW. Holli places in as the seductive and destructive lure of that world, and if we stick with this logic, removing the Spike shows what happens when that lack of intention with regards to creation gets out of control. It is shown to be ultimately unfulfilling and potentially destructive. In the end, while Jack does replace the Spike, he's consumed by his own id (becoming animated and stuck with Holli). Harris on the other hand, through his resurrection as a doodle, embraces his own imagination. So thematically, Cool World wants us to know that we can't deny our creative impulses, but we shouldn't give into them either.
Of course, it's also a terrible movie that was put through a blender by the Hollywood system. I can't necessarily say that any of this really works, but it was fun to think about while listening to the episode. Thanks for that, guys.
