The Indus Dictionary Project
This is Mahadevan's sign number 2518, which I have redrawn based on a photograph of seal M-68. It is the singular and plural noun snake.
The symbol is a pictograph of a snake. The downward strokes evoke snake strike action.
Mohenjo-daro: Seal: M-68 a: Jagat Pati Joshi and Asko Parpola, 1987: Corpus of Indus Seals and Inscriptions: Volume 1: Page 30: Collections in India: Suomalainen Tiedeakatemia.
Snake: Lynn Fawcett, 2017.