A 32-year-old woman with a giant vertebrobasilar junction aneurysm underwent a Hunterian coil occlusion. Two months later she was readmitted with aggravation of her previous symptoms. Shortly after the admission, fatal bleeding occurred. She underwent emergency surgery and the aneurysm was trapped by clipping at the vertebrobasilar junction; however, she died. For treating unclippable giant vertebrobasilar aneurysms, proximal vertebral occlusion is an alternative. By occluding the proximal parent artery, we expect reduced inflow of blood into the aneurysm and thereby induce intra-aneurysmal thrombus formation. Based on the experience with this patient in which the hemodynamics resulted in continued pressure on the inner wall of the giant aneurysm, we postulate that Pascal's law might play a role in the rupture of a giant aneurysm after Hunterian occlusion.