Ushnisha
The ushnisha (, IAST: ) is a three-dimensional oval at the top of the head of the Buddha. Description. The Ushnisha is the thirty-second of the 32 major marks of the Buddha. The thirty-second of these is that the Buddha has a fleshy or cranial protuberance at the top of his head. Later sets elaborate that this is covered with hairs that curl in the direction of the sun. Later on a second definition of Ushnisha was added, which was a flame that ascends from the middle of this protuberance. Representation. The first representations of the Buddha in  the 1st century CE in the Greco-Buddhist art of Gandhara also represent him with a topknot, rather than just a cranial knob. It is thought that the interpretation of the ushnisha as a supernatural cranial protuberance happened at a later date, as the representation of the topknot became more symbolic and its original meaning was lost. Origins. While the ushnisha is an important feature of Buddha statues and images, there is no evidence that Buddha had a topknot on his head. Ancient books clearly state that Buddha had a shaven head. One event mentioned in the texts is where  a hunter while out on a hunt encounters Gautama Buddha (prince of Lumbini) in a different attire than that a prince should had. The hunter is mentioned as giving up hunting for the day, after seeing the shaven man in the middle of the jungle, considering it to be a bad omen. The Boddhisattva-Cakravartin in Early Buddhism. In Early Buddhism, the was represented differently. The "Mahāvastu" (1.259f) and the "Divyāvadāna", as well as the Theravadin "Milindapañha", describe the marks of the cakravartin, an idealised world-ruler: or "patka" turban, "chhatra" parasol, "horn jewel" or "vajra", whisk and sandals. These  were the marks of the kshatriya. The plastic art of early Mahayana Buddhism in Mathura presents bodhisattvas in a form called "wearing a turban/hair binding", wielding the mudras for "nonviolent cakravartin rule". Possible Indus Valley origins. A bull figurine excavated from Lakhan-jo-Daro from bronze age Indus Valley Civilization has a similar Ushnisha styled knob above its head, its a unique feature and not applied to any other bull figurine indicating intelligence insignia. See also. The crown-protrusion, mentioned in https://en.m.wikipedia.org/wiki/Classes_of_Tantra_in_Tibetan_Buddhism is this same upper-brain-blossoming/development, simply with a different label.