Found in a barn cleanup. It’s a heavy iron tool with a hinge and jagged teeth on the inside curve. It opens and closes but I have no idea what it’s meant to grab…  

That description actually points pretty clearly to an old agricultural gripping tool—most likely a hay or ice tongs.

Here’s why that fits what you found:

• Heavy iron construction → built for tough, outdoor farm or storage work
• Hinge mechanism → allows it to open/close like a clamp
• Curved jaws with jagged teeth → designed to bite into something slippery or fibrous
• Barn context → exactly where tools like this were commonly used

Most likely options

1. Hay Tongs

• Used to grab and lift bundles of hay or straw
• The teeth help grip the loose material without slipping
• Often used with a rope or pulley in barns to move hay to lofts