corrupted pleasant, pleasant falls - SM64 B3313 (1.0)
A few things to note:
1. at 2:04, you can see a platform on the parallel 'hill', I've been there before and it does nothing.. If you continue down that way it leads into a broken part of the mountain which is hard to get out of.
2. This level is pretty dangerous as it's very easy to get stuck, a good example is the end of this video. There are numerous points like that on this map. I'm not sure if this 'corrupted' variant is intentional or not, but it is interesting.