How Vardhaman became Mahavir
Young prince Vardhaman was playing on a tree in a garden with his friends.
A deva named Sangam came to test his courage. He took the form of a huge snake and wound himself around the tree.
All the other children got scared and jumped down. Vardhaman was not afraid at all. He climbed onto the snake and played as calmly as if he were on his mother's bed.
Filled with joy, Sangam deva praised him and gave him the name Mahavir, the great brave one.
Source: Uttar Puran, Acharya Gunabhadra (page 491)