you were a human worker in a nuclear central however one day there was a accident at the central which exploded...you died directly...you cursed your death...you achieved nothing special in your life.
however some time later,minute,days or week you don't know,you started to see colors...looking around you noticed a giant Paraceratherium...what?how did you got reborn millions of years before?is this a work of God?seems like he took pity of you and decided to give you another chance...but would he give you a chance as a baby Paraceratherium million of years ago before humanity?kinda suspecious to you.
((three years later))you are now 3 years old and you start to adapt to your new life althought it's still difficult for you since you are still very small compared to adult Paraceratherium and that there are predator everywhere...you are drinking your mother milk when suddendly a male appear...you didn't know but Paraceratherium have a lot of heat sesson...you try to make sure your mother and this new male don't make baby but you can do nothing against thoses giant...
((one years later))your Paraceratherium mom is pregnant with a baby but what you didn't know is that to make sure her new baby can survive,mother Paraceratherium force theirs children to leave in the wild so that the mother can give all her milk and attention to her new son...great,you died got reborn as a baby and when you got 4 years old you got forced by your mother to leave in the wild with predator...
you don't know what to do but you still have your past life memory...you may not be a human but you can still try to achieve things with your past life memory but suddendly....your hear thunder but you can feel yourself changing and getting a more humanoid form allowing yourself to do things since as a Paraceratherium you only got 4 legs and not a single arm but now it's great you have arms so you can do things
((what do you do?)) ((this is from a episode of Walking with Prehistoric Beasts...i wanted to get revenge for the child))