I had thought it may be a drilled out Tektite (ejecta from a meteorite impact), if it had not been magnetic at all- Some of them look quite similar in shape and surface appearance. But- tektites are not magnetic because they are not crystalline. Usually they are formed from some sort of sand or whatever the surface was that melted during the impact.

Dumbbell shaped tektite for reference

However, Some Tektites can contain microscopic Ni-Fe spheroids (Nickel-Iron), so this is a possibility. https://gsw.silverchair-cdn.com/gsw/Content_public/Journal/ammin/52/5-6/am-1967-721/1/am-1967-721.pdf.gif?Expires=1552686410&Signature=LiGKFAjHty9wI~e9kZoO7Tu2UsCM8ZA8GY6w~sU0sCat9~gLMIvwZN3vtY5GBZsIK8-aQEhr9SmdTDw15LPu-PV79fgY3XJBW-W7ynun6ONRIiu46sw7EA3h3MWKyp-L5eEAbnrPKj3DT~lIWRPPGoAY~6Nwvd8fGGteKhT3Ry1leFShX06BJb0d3KDA9ZL3TYv6Vm3XLtk4mHeWdeOTdJ6VZqxYvN0GS4Kqaa2~iz585F6N-S5OgwVbJs0S864yP-2EzU5OYy~o-W1RszQYuWEzVPVcinZu9XVDprFu9nocfSLY5pxwjPjEJsNYX2-WZR2N0Y~FWfUTnUCaKQczsA__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA

The above abstract indicated varying % of Ni-Fe spheroids in some tektites. Impactite glass bombs from the Meteor Crater, AZ area can contain from 20 to 65 weight percent nickel. . Not sure if that would even be enough to account for weak magnetism. Still reading... Evidently the metallic spherules are introduced either from the meteor itself or from the impact site, and can be contained within the tektite or as a "coating" of sorts.

So, onward. Still thinking.