JumpJet Rex

This achievement requires you to die and turn into ash a great number of times in a single level. This can be done by fire, electricity, or laser beams. I personally used the level Intruder in the second world (after beating the Yeti). It is a short level with essentially an electric cage all around it with two laser beams in the middle with a laser cannon between them. You can use rocket (Y button) to push yourself against the roof and electrify yourself. What is also nice is that if you die by any other means (laser beams or turret) you will still be turned to ash. You can easily spread your ashes over the course of the entire length of the level. This took me about 3 minutes or so until it popped. If you have any problems or comments, please let me know.

Best of luck.

Hello guys !

For that cheevo you'll need to die a lot with the fire to transform your T-Rex in ashes.The best level for that is Jungle Jump in World 3.I needed to die ~50 times in the level to unlocked the cheevo.If you have some problems with that change your spot and die in more places,it should be good

Happy hunting !

The achievement only pops onces you complete the level

Like the other guides say go to a level with lasers/electricity/fire/fireballs or anything else that turns your rex into ashes when you die. I went to Jungle Jump which is after the 2nd boss. Die and turn into ashes in multiple places around the level. Die around 50 times (the exact number is unknown) then finish the level. The achievement only pops onces you complete the level. I died more times than I had to because I didn't know it only popped when you finish. Good luck