Charles Ellicott Commentary Numbers 21:10

"And the children of Israel journeyed, and encamped in Oboth." — Numbers 21:10 (ASV)

And pitched in Oboth.— The intermediate stations between Mount Hor and Oboth were Zalmonah and Punon (Numbers 33:41–43). The former of these places is thought by some to have derived its name from the Hebrew word zelem (image, or likeness), and to have been the place at which the likeness of the serpents which bit the Israelites was set up.