What is foreshadowed in the story "A Sound of Thunder"?
There are, indeed, several hints of things to come in Bradbury's short story. When Eckels arrives at the Time Safari, Inc., he swallows hard and "a warm phlegm gathered" in his throat. Evidently, he is nervous about his trip to hunt the Tyrannosaurus Rex. When he asks if the safari guarantees that he will return, the official tells him that his company has no guarantee upon anything but "the dinosaurs." He also adds,
If you disobey instructions, there's a stiff penalty of another ten thousand dollars, plus possible government action, on your return."
And, as Eckels looks around, he notices
a sound like a gigantic bonfire burning all of Time, all the years and all the parchment calendars, all the hours piled high and set aflame.
Here are suggestions that something serious may happen with the manipulation of "Time" if things do not go as calculated. As he waits, Eckels talks about the recent election, grateful that the man who has won the presidential election is in office since his opponent would have created a dictatorship. The official assures him that all he has to worry about is shooting his dinosaur.
The foreshadowing here is that the outcomes of the present time may change, Eckels may have trouble shooting his dinosaur, and he may have to pay a penalty for disobeying instructions.