I've got napalm working, with the help of Winner5740. There's still a lot I have to tweak about it to make it look right, but I've basically got a TNT block that will spawn fire around it. I also have a grenade that does the same thing. I plan on making a napalm fire block that will act differently than normal fire in that it will stick to more things, stack on each other, fall like sand and gravel, and won't go out if there's air under it. This napalm thing has been bugging me for a while now and hanging over my head. It looks like it's pretty much all downhill from now on.
Another thing I fixed today was the cobra. Like the elephant, it will attack you back when you attack it. I was going to try to make it drain your health over time like you were slowly dying from the venom, but the thing just attacks so fast that it would kill you before you even had a chance to drain health, so I think I'm just going to leave it like that. Oh, and it drops the slime balls to make sticky pistons. I just renamed the slime ball to "snake oil". The Elephants drop ivory and the turtles drop turtle shells, which are both used to make armor. I'm really having a hard time thinking up something good to craft with ivory and turtle shells, but since I got elephants and turtles in the game, what else could they drop? If you got any suggestions, please feel free to send them my way.