Violations of weak cosmic censorship in black hole collisions

 We simulate collisions of stable rotating black holes in six and seven dimensions. We find that if the angular momentum of the system is sufficiently large, the post-merger configuration is an elongated dumbbell which is Gregory-Laflamme unstable. As such, it displays a cascade of satellite formation which ultimately leads to pinching off of the horizon, thus violating the weak cosmic censorship conjecture.