Plot Boulder
A random point in a story, usually in rpg video games, where a character will be prevented from moving on until they have accomplished another story event somewhere else.
Johnny: I need to go to the next town, but they keep telling me the road to it needs to be repaired.
Alex: It's a plot boulder. Go do something else with the story and it should be gone afterwords.
Alex: It's a plot boulder. Go do something else with the story and it should be gone afterwords.