Putana
When Lord Krishna was a 1 month old baby, Putana the demoness was sent by Kamsa to kill Krishna. She took baby Krishna in lap and fed poison milk. Krishna sucked out her life-air and gave her liberation.
Trinavarta
Trinavarta the whirlwind demon picked 1 year old Krishna and rose up in the sky. Krishna made Himself heavy, so much so that Trinavarta fell on the ground unable to bear His weight.
Aghasura
When Krishna and His friends entered the mouth of Aghasura in the form of a giant python, he swallowed them. Krishna tore open the stomach and they all came out alive.
Govardhan
Indra wanted to punish the people of Gokul for not performing Indra puja. To protect His people, Krishna lifted the Govardhan hill for seven days and seven nights. Finally, Indra gave up and begged for forgiveness.
Subduing Kaliya snake
A multi-hooded snake Kaliya had taken residence in Yamuna river and was poisoning the water. Krishna dived into the river and subdued Kaliya, dancing on his hoods. This was a spectacular dance witnessed by the Gods.
KIlling of Kamsa
At the age of 12, Krishna and Balarama went to Mathura and over-powered the wrestlers Chanur and Mushtik. He killed Kamsa and enthroned Kamsa’s father Ugrasena as the king of Mathura.
Studies
At Sandipani muni’s school, after hearing only once from the teacher, Krishna and Balarama learned all the arts and sciences. In 64 days and 64 nights, they learned all the arts that are required in human society.