Starting off a human by the name of xxxx, expert in science and mechanizing, a prodigy at 12 he created a new element, in his fifteenth of age he formulated a theory of other dimensions existing. He mastered computer science and programming at eighteen and self-taught himself forty-four languages, didn't bother to study more because forty is his favorite number.
At twenty-one he was invited to a lab and was made leader of the new project they are researching. It was the key to enter another dimension, he was funded, with all his knowledge and skills combined with other people, a portal was made.
He poured all his forty years of life and made a breakthrough, the prototype of a portal as the result. However there was a huge price lost in having this made into reality, that was, the portal was too chaotic and unknown frequency is transmitted every set of time which sounded unknown.
Upon there, he who poured all his life for this project to be made, even if it's a prototype, he was the first to test it, ignoring the higher-ups order.
He entered, after entering the portal closed itself and all his equipment failed to work, communication was cut, not only is his way to find home gone, unknown to him this was an underlying curse even to him, a curse so potent that soon he would come to realize.
Looking around there was plain grass taller than him. Trees are thicker and taller than it reach the skies, insects size as big as cars and then, when he looked around he spotted something that wasn't in his time, a T-Rex.
He dropped to his knees in a loss, all his research going into the creation of ways to enter another dimension was poured into creating this machine. That machine that lets you enter the past, he gritted his teeth and stood up ready to run, but he was too late as the T-Rex saw him grovelling on the ground.
Seconds before he could run, he was devoured, minutes passed, pain came later, he was spotted out, he looked at himself down to his hand, he was... Fine? Before he can thought of another word to spill out of his mouth he was devoured again, bones breaking, blood seeping out, with a crunch he made it into the stomach of the T-Rex.
He regenerated again, his torn broken equipment made him wail in pain, until he made it out, naked inside the belly of the beast that had eaten it.
Never time to think now, he was now immortal, the properties of the portal into this world affected his time and thus his body stopped it's movement, he moved like a semi-dead like state, like an undead but alive. His body is outside of time now so any thing that hurt or changes his body, then everything will revert to what he looked like when he was before he entered the portal.
The T-Rex happily walked back to its den, expelled him from its belly, the T-Rex looked at the human before it did not understand how it survived, the human before him were almost eviscerated and scratch marks were in place.
To the human, his body itched, it itched so much that his blood and organs spilling blood didn't matter as he continued to dig it out and end up dying before being reverted again back in place.
The T-Rex ignored what had happened to this human and end up eating it up again.