Whats the name of this movie where they kill a dinosaur as a sport but when its

[chunky1203dany]

just about to die in the tar? A group of people are on this path and they cant get off it of they'll mess with the future, and this dinosaur comes and they kill it right before its about to die in the tar pit..... And they keep going back because they messed up the future

 

[Matt]

It's the Ray Bradbury book turned movie A Sound of Thunder