Some time back I read some passage somewhere (I know LOL) where a dhāraṇī was given, and one of the key results of reciting this mantra was that the person would be able to understand the speech of animals.
Now I can't for the life of me find this, even though I know its in one of my books.
I think it was given by demons or nagas, and not recited by a Boddhisattva or Buddha. I thought it was connected to Medicine Buddha, but it could be from Lotus Sutra.
Ring any bells for anyone? I'm not seeing much on google that is helping.