According to our current understanding of physics, objects with mass cannot travel faster than the speed of light. Therefore, the scenario you describe—two black holes traveling faster than light and colliding—is not possible within the framework of known physical laws.
However, let's consider a hypothetical scenario where two black holes, each with a significant mass, were somehow moving at extremely high speeds close to the speed of light and then collided. In such a situation, several outcomes could be expected:
Increased Mass and Energy: When black holes collide, they merge to form a larger black hole. The combined mass of the two initial black holes would contribute to the mass of the resulting black hole. Additionally, a significant amount of gravitational potential energy would be released in the form of gravitational waves.
Gravitational Waves: The collision of two black holes at any speed would generate powerful gravitational waves, ripples in the fabric of spacetime. These gravitational waves carry away energy and momentum from the system, causing the newly formed black hole to recoil or radiate gravitational waves.
Event Horizon and Singularity: The event horizon, the boundary beyond which nothing can escape a black hole's gravitational pull, would still be present in the merged black hole. The singularity, a region of infinite density at the center of a black hole, would also persist.
It's important to note that the behavior of black holes under extreme conditions, such as high velocities near the speed of light, is an area of active scientific research. Our current understanding is based on the laws of general relativity, but a complete theory of quantum gravity is still elusive, and it may provide further insights into such scenarios.