"Jon Klingelmann" is an archaic Norwegian name given to a serpent.
From The Black Books of Elverum, Mary S. Rustad edition:
To weaken the poison from a snake
"Jesus and St. Peter walked down a road. There they met a dead man. 'What has killed you?' Jesus said. 'Jon Klingelmann has stabbed me,' replied the dead man. Jesus said, 'Stand up and you shall be healed instantly.' In the name of the Holy Trinity." Recite the Lord's Prayer three times.
The grimoire The Black Books of Elverum lists this spell.
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