Continuity mistake: After Ganon is thrown from his skeleton drawn throne, he summons more of his skeleton minions through an underworld entrance cave that pops up from the ground in the middle of the road. Link hands Zelda the bone bow as it pops up and she looks back surprised at it. In this shot, the cave entrance is a perfect triangle shape, and there are no horn structures above the opening. Then it cuts to a closer view of the entrance as the Skeletons begin marching out. Now the underworld entrance has more curved shapes to it rather than strange lines making it triangle, and horn like structures appear above the opening. The rubble around the opening that came up from the road as it rose up also changes in shape.
Picture added by Quantom X