Rod, very rare (requires attunement)
This rough, iron rod is spiked at one end and scarred by several gouges across its surface. You can use an Action to plant the rod in the ground creating an antimagic field. The field is disabled if the rod is knocked over with a successful DC 10 Strength check, or if the creature that activated it uses any magical item or spell (no matter where they are). Otherwise, the field lasts 1 minute.
After being activated, the rod can’t be activated again until it has been dealt any amount of slashing damage after the next dawn. After taking 20 points of slashing damage, the rod ceases to function.