The scene contains an object with a spawning script and an assigned prefab. The prefab itself has the same spawning component script set to spawn the prefab itself. As a result every prefab created then creates more of the same prefab in its Start(), multiplying until the machine runs out of memory and freezes or crashes.
This can be resolved by removing the spawning component on the prefab itself while keeping the spawning object in the scene.
If self-spawning was intended the recursion needs a base case like a depth counter that decrements per level so it does not multiply without ending.