13 Vrischikasana

We are bringing the feet to our head to symbolise the stinging of the ego. 
The feet, which kind of symbolise the most humble part of our body, the ones that touch the earth are now coming to the top of the head, 
the place in our body that is probably most revered.
The feet touching the head is a symbol of the connection, that nothing is really higher or better than something else.

“The head which is the seat of knowledge and power is also the seat of pride, anger, hatred, jealousy, intolerance and malice. 
These emotions are more deadly than the poison which the scorpion carries in its sting. 
The yogi, by stamping on his head with his feet, attempts to eradicate these self-destroying emotions and passions. 
By kicking his head he seeks to develop humility, calmness and tolerance and thus to be free of ego. 
The subjugation of the ego leads to harmony and happiness.”
(BKS Iyengar)