I've had this basic idea where the biodiesel exhaust caused hefty individuals to swarm the car like zombies from the movies for a bit. In fact, I was going to do it as a "A Zombie's Survival Guide" comic not too long ago, but when I sat down to work towards it... it just wasn't something that fit that kind of comic. So, I shelved it for a while. I came up with having the guys have gone passed "fat row", if you will, where all the weight loss establishments are clustered and that spurred the swarm. For some reason fast food restaurants seem to cluster together, why not their opposition? I'm just saying if that were to happen... a Baskin Robins would clean up if it moved in the area. The biodiesel engine wasn't something I wanted to keep in the comic forever. This comic was something I wanted to do before I got rid of it or stopped mentioning it... but, this seems like as good a reason as any to have John revert the engine to good ol' fossil fuels... even if the price at the pump is astronomical... it's just a wacky and weird little fact that folks coming to the comic wouldn't know and any further mentions of it down the road could possibly confuse them.