Place it at the turning point of a fail edit, just before the reaction shot. Follow it with Vine Boom to underline the impact, or lead into it with Dun Dun Dun when the block is building. Keep the surrounding shots short so the obstacle stays the focus of the scene.
Über diesen Sound
An Obstacle is a short sound effect lasting about seven seconds, centered on a sudden block that stops progress in its tracks. It feels abrupt and comically frustrating, like a plan collapsing just as it starts to work, and it leaves a clear beat for a reaction. The effect works best as a single sharp interruption rather than background noise.