>In 2017 the New Zealand Parliament passed the Te Awa Tupua (Whanganui River Claims Settlement) Act, which granted the Whanganui river a ‘legal personality’ and endowed it with “all the corresponding rights, duties, and liabilities of a legal person”.
It's less silly if one thinks of it as the New Zealand Parliament created a Whanganui River Authority and endowed it with the same structure and rights.
You can jail it by building a dam, or banish it from areas by redirecting the river around them, or insert a water wheel and sentence it to forced labor.
Unexpected indeed, interesting!