What happens if a black hole interacts with another blackhole?

A black hole can be thought of as a region of space that has extremely high gravitational pull and not even light can escape it. If two black holes were to collide, one of the following two scenarios may results:
1) The two colliding black holes will start spinning around each other, coming closer and closer to each other and will finally merge into each other, forming a much larger black hole. The resulting black hole will be known as a binary black hole. This event will create massive ripples in the spacetime fabric. Such ripples are known as gravitational waves.
2) The other outcome would involve the larger black hole throwing the smaller black hole away.
The outcome of the collision of two black holes is a function of the speed at which they are traveling, the angle of collision and how fast they are spinning.
Hope this helps.