https://www.youtube.com/watch?v=iWKFPTgkpXo
Basically inspired by this video and its comparison with wormholes. While many other questions on the site have already covered the weak strength of gravitational waves and hence hinting the experimental feasibility, what will happen in theory when there are gravitational waves of sufficient energy to converge to a point. Do we end up with a black hole similar to how a kugleblitz works or we don't know because at the focal point, the strength of gravity will be so strong that it is no longer obeying the weak field limit and hence require a quantum gravity description?
The only thing I am certain without doing some pretty computationally intensive numerical modelling is that since gravitational waves are nonlinear, they cannot be expected to just add up in superposition, so the resulting wave may not be a spike wave.