u/DeadMeme2003

"Late Cretaceous, Ojo Alamo Formation in New Mexico, the absolute southernmost point of his territory. A Tyrannosaurus rex stalks a half mile behind a herd of Alamosaurus. He's been following them for days now, waiting. Watching. He knows he can't take on a healthy adult, that's suicide. But there's one individual he's focused on. It's old, limping, straggling at the back of the herd. All he has to do is keep walking, and wait for it to trip and fall.

For an Alamosaurus, "elderly" means easily eighty years old and older. This giant has lived an incredibly long life, fought countless battles, and survived impossible odds. But its strength is waning, and its body is beginning to fail.

The ancient titan bellows in surprise as its right arm suddenly buckles and gives out, and the T. rex can hear all the way from a half mile back. He can hear and feel the hard thud of a giant, eighty-ton body hitting the dirt. This is his chance. He picks up his pace to a leisurely jog, he's unable to sprint. By the time he catches up, the Alamosaurus is struggling to breathe as its lungs are crushed under its own weight, lying on its side on the ground. The tyrant circles the Sauropod, stepping well clear of the heavy, twitching tail. He finds the giant's head, and delivers a crushing bite to the neck just below the skull, crushing the Alamosaurus's windpipe and killing the titan.

He can now begin a feast that will last him weeks. All he needs to worry about now is scavengers."

I've written a documentary style scenario about this before

"Northern New Mexico, the absolute southernmost point of his territory. A Tyrannosaurus rex stalks a half mile behind a herd of Alamosaurus. He's been following them for days now, waiting. Watching. He knows he can't take on a healthy adult, that's suicide. But there's one individual he's focused on. It's old, limping, straggling at the back of the herd. All he has to do is keep walking, and wait for it to trip and fall.

For an Alamosaurus, "elderly" means easily eighty years old and older. This giant has lived an incredibly long life, fought countless battles, and survived impossible odds. But its strength is waning, and its body is beginning to fail.

The ancient titan bellows in surprise as its right arm suddenly buckles and gives out, and the T. rex can hear all the way from a half mile back. He can hear the hard thud of a giant body hitting the dirt. This is his chance. He picks up his pace to a leisurely jog, he's unable to sprint. By the time he catches up, the Alamosaurus is struggling to breathe as its organs are crushed under its own weight, lying on its side on the ground. The tyrant circles the Sauropod, stepping well clear of the heavy, twitching tail. He finds the giant's head, and delivers a crushing bite to the neck just below the skull, crushing the Alamosaurus's windpipe and killing the titan.

He can now begin a feast that will last him weeks."