Mahima siddhi is the ability to acquire enormous size. Several examples of this superpower are found in Hindu mythology. In one legend, Hanuman assumed a large form to burn Lanka and to fight Kumbha Karma. In another, Vishnu expanded to such a huge size that he was able to cover all three worlds in just three steps. Hanuman and Vishnu not only possessed all eight siddhis, but also had the ability to pass these superpowers on to others.
There is also a psychic power connected to mahima siddhi called "clairvoyance," or "far seeing." It is believed that only very advanced yogis may achieve mahima siddhi, or any one of the other eight primary siddhis. Even when he/she does, the yogi rarely reveals this achievement.