Game of Thrones often left its viewers in a bad mood, frequently "killing off" beloved characters. However, at times, the show delicately warned fans about the impending death of yet another hero. While it's unlikely that any viewer figured out the true purpose of these scenes, Game of Thrones did indeed "spoil" a bad ending for the show's favorites—twice, in fact.
A scene in the pilot episode of the first season clearly hinted at Ned Stark's death.
Fans will likely remember this scene, which features Ned Stark walking with his children deep into the woods, where they discover the pups of a direwolf. Nearby, they also find the corpse of an adult direwolf, killed by deer antlers—this is where the writers' hint lies, as the direwolf was an unofficial symbol of House Stark, while the image of the deer was present in the emblem of House Baratheon. As we know, Ned Stark was sentenced to death by order of Joffrey Baratheon.
The demise of Robert Baratheon was also foreshadowed.
However, this occurs in a different episode of the first season—the episode opens with a scene in which Tywin Lannister is butchering a deer. At first glance, it may seem that there is nothing profound about this; after all, Tywin, like many others in Game of Thrones, was fond of hunting. However, there is indeed a deeper meaning here—the scene represents the victory of the lion (the symbol of House Lannister) over the deer (the symbol of House Baratheon), as after Robert Baratheon's death, power and the throne effectively passed to the Lannister family.