Slow Havamal: 151

In verse 151, Odin says the sixth spell he knows is for when someone carves a curse against him in the roots of a tree. He calls the spell down on its carver so it harms him instead of Odin.

We see attestation in the sagas of people carving curses in the roots of trees, presumably in runes. A woman uses one against Grettir, and he cuts himself and gets an infection when trying to chop it up, which leads to his death. Sounds like he could have used Odin’s spell.( Read more... )