JumpJet Rex

I grinded this on the level Flow Rider. Which is right after Boot Camp on the top. At the beginning of the level there are spikes right where you start. So just hold right on the left stick and never let go. Your character will continue to die over and over running into the spikes. Since it is the very beginning of the level you do not have to worry about restarting yourself. The game will do it automatically. So just keep holding the stick until the achievement pops. I already had about 50 deaths and it took me 45 mins to get 500, so if you are starting from zero it will probably take around an hour to do. The achievement will pop right on your 500th death.