In addition, I think it may be interesting to consider if the relationship between Key and Toon works in reverse, to a certain degree.
For instance, a Key may create a toon, his or her masterpiece, creating life from the vapor of nuance. And surely, once alive, it has free will, intelligence (of sorts), personal agendas, etc. And of course, a toon enriches the life of the Key, promoting success, gaining a valuable sidekick, or even just a friend in a time of need. . . Benefits, in other words.
But what happens when a toon is killed by Dip? We all know that Dip destroys the creative potential, sealing off toons from the otherverse of imagination that fuels their powers and life-essence. They melt, they fade, they die. And Dip even damages humans in a certain way. Human Dip addicts burn out, lose focus, and their minds. They become empty husks, unable to laugh, cry, or even Imagine. Like human robots.
But my question is this. What if the Key's one true masterpiece, his greatest toon companion, his killed by Dip. His creation, and creative essence stripped from this work, forcibly. Maybe this will have some backlash on the Key. Similiar to Shadowrun Drain, or DnD-esque con loss (Charisma loss?) from death of a familiar or animal companion? I think that Toon-Death should have an adverse effect on the Key that created it. Or at least a mental pinging that they had "forgotten something. . . Seemed important, but. . . "
For that matter, as a Toon is dipped, does it fade from the collective unconscious? Does it become a 'Neverwas'. Hard to track Toon-murderers, when you never knew a Toon existed, after all. . .