In Chinook mythology Frog was given fiber by his relatives Snake and omnipotent Coyote. With this fiber, Frog was given the task of creating the cordage for the weaving of the first fishing net.
With this net, made from fibers of the nettle, Frog had made it possible for the new human beings to catch their first salmon.
Coyote tested this net, with the guidance and wisdom of his three sisters, establishing the complex set of taboos associated with the catching of the first salmon of the season.
The new people would never eat or harm Frog, for his cleverness to human beings protected him. That is why you should always step around Frog and never over him.