Pashupati seal
The Pashupati seal (also Mahayogi seal, Proto-Śiva seal the adjective “so-called” sometimes applied to “Pashupati”), is a steatite seal which was uncovered in Mohenjo-daro, now in modern day Pakistan, a major urban site of the Indus Valley civilisation (“IVC”), during excavations in 1928 or 1929, when the region was under British rule. The excavations were carried out by the Archaeological Survey of India, the official body responsible for preservation and excavation. The seal depicts a seated figure that is possibly tricephalic (having three heads). The seated figure has been thought to be ithyphallic (having an erect penis), an interpretation that has been questioned by many, but was still held by the IVC specialist Jonathan Mark Kenoyer in a publication of 2003. The man has a horned headdress and is surrounded by animals. He may represent a horned deity.
It has one of the more complicated designs in the thousands of seals found from the Indus Valley civilization, and is unusual in having a human figure as the main and largest element; in most seals this is an animal. It had been claimed to be one of the earliest depictions of the Hindu god Shiva—“Pashupati” (Lord of animals) being one of his epithets, or a “proto-Shiva” deity.
Though the combination of elements in the Pashupati seal is unique, there are a group of other Indus seals that have some of them. One, also from Mohenjo-daro (find number DK 12050) and now in Islamabad, has a nude three-faced horned deity seated on a throne in a yogic position, wearing bangles on its arms. In this case no animals are depicted, and there is some dispute as to the gender of the figure, despite it seeming to have a beard.
The Pashupati seal is in the National Museum of India, having been moved there with the other Mohenjo-daro finds before independence. These were reserved for the future national museum, finally founded in 1949, and the seal was allocated to the Dominion of India at Partition in 1947.

By unknown Indus Valley Civilization sealmaker from Mohenjodaro archaeological site - http://www.columbia.edu/itc/mealac/pritchett/00routesdata/bce_500back/indusvalley/protoshiva/protoshiva.jpg, Public Domain, https://commons.wikimedia.org/w/index.php?curid=9325528