The hero says, "Well, let's set up camp here for the night." A quick scene change later, and we see him ineffectually hammering one last tent-spike into the ground, finishing up what is an otherwise fully constructed tent, complete with roaring campfire, a cord of firewood, a crude fence, and all this in a level clearing that did not exist before.
Yet the hero shows no signs of fatigue- he obviously had a little help. As in, it was built like any other set and he's walked up and taken credit for it with his little tent-spike driving hammer.
This is distinct from tropes about scenery since it can apply to anything where the results of the character's physical labors are clearly not his own- a cool sword the hero just forged, or some other physical prop, is just as valid. What makes this trope is the fact that although we are given signs to accept the work as the character's own, we only see them at work in the very final stages, if at all.