This is a pictograph of a loop on the end of a length of rope, in other words a lasso. Hence, it is an ideograph for the verb to catch.
Illustrative Text Reference:
Mohenjo-daro: Seal: M-34 a: Jagat Pati Joshi and Asko Parpola, 1987: Corpus of Indus Seals and Inscriptions: Volume 1: Page 18: Collections in India: Suomalainen Tiedeakatemia.
Image Credit:
Indus Script Sign Number 396: Sign List of the Indus Script: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.