The Wikipedia page doesn’t seem to mention the craziness of the oaths to the point of gods, but seems to be more about boastful things people would actually try to do.
From the above link:
Heitstrengingar took place at Yule and other sacrificial feasts, weddings, arvals, and banquets and often acted as a form of bragging and promising the performance of an often great feat.
Which seems to have been extrapolated on a bit for the post.
I believe this refers to Heitstrenging.
The Wikipedia page doesn’t seem to mention the craziness of the oaths to the point of gods, but seems to be more about boastful things people would actually try to do. From the above link:
Which seems to have been extrapolated on a bit for the post.