Wikipedia
Mahakal
According to Hinduism, Mahakal refers to lord Shiva as he is the destroyer of all elements. There is nothing beyond him, no element no dimensions not even time (kaal). That is why he is maha (greater) kaal (time). Kaal is the time of death so it can also be reference as bringer of the greatest time of death, death of all that is. The Tandava he performed when his wife Mata Sati jumped into the fire as she could not bear the disrespect of her husband by Raja Daksh (he was the father of Sati ) during a havan. This was the moment when Shiva was about to destroy the world. Thus he is known as "Mahakal". Rather than just bad elements he is the destroyer of enemies.