What is the backstory of the knife in Jeeper Creepers 2?

Tools of the Creeper - wikia

The Creeper employs a variety of weapons in his pursuit for food. He commonly carries daggers and throwing stars made from the flesh and bones of his victims. He also uses a medieval battle axe in the first film, which was destroyed after Trish hit him with her car. The weapons he creates are shown to move of their own accord (or perhaps return to their master) in the second film, where a knife flies across a room under its own power, traveling through a leather lamp before embedding into a nearby wall (a possible sign that they travel towards flesh). In theory, it could be that the creeper has some sort of psychic connection with his weapons (more specifically this knife). Additionally, the father strategically decides to use it as a tip to his harpoon to hunt the Creeper. Perhaps another fine example of the Creeper's weapons and obsession with his victims would be a small razor-disk like object that he used to flatten the school buses tires in Jeepers Creepers 2, which appeared to have been crafted out of Darry's flesh as it had his belly-button and rose tattoo on it. The blades themselves are likely to be Darry's bones (it is unknown that they are). Another example of his attachment to victims can be shown with Billy Taggart. In the scene where Jack Taggart Sr. appears to be sharpening a knife to use for the harpoon, notice the previously mentioned knife that "mysteriously flew" across the room. On the handle, there is cryptic, free-hand drawing of the creeper pursuing a frightened Billy inside the cornfields.

The Creeper also drives a very large, old-fashioned, rusted-looking delivery truck which he uses to transport bodies and scare victims to get a scent from their fear.