Hi,
this is yet another unmissable achievement and most likely the 2nd achievement you'll unlock in the game.
This will unlock at the beginnig of chapter 1-5 (Dark Forst V). You will be introduced to the gene splicer which can be used to transform the ME into a jellosaur
Go back a few steps and you'll see a template of a dinosaur. There are arrows going from the left side of this template to the right side. Jump with the direction of these arrows to transform the ME and the achievement unlocks.
If you don't know what I am talking about you can watch the video right here: Go to minute 7:30 to find the part I was talking about.
(video credit: emozaga)
Hope this helps you guys!
Any improvements? Please let me know in the comments below!