Chakravyuha (cakravyūha)

The chakravyuha is a wheel or spiral formation of concentric rotating rings, considered almost impossible to break and harder still to leave. Drona arrays it on the thirteenth day specifically because only Krishna, Arjuna and Pradyumna are believed to know the way out, and both are drawn away from the field. Abhimanyu, who heard how to enter it in his mother's womb but not how to escape, breaks in alone and is killed by six great warriors at once, in the single act that turns the war from a battle into a blood feud.