Well, this is clearly a porcupine trundling down from the peak one late evening.
but what about this?
Well, when i put this picture into the excellent iNaturalist APP and asked its normally excellent image recognition software to identify the caterpillar it also gave me "Porcupine". (and thanks to Jon Yang for ID of the above, which is probably Macrobrochis gigas, or some other species from Arctiinae.
I think from these images below, its easy to see why the APP could be confused!!
Nonetheless i still use the iNaturalist APP a lot to identify and record my observations in the wild. It works for animals and plants too. Download the APP, or go to https://www.inaturalist.org/ to find out more. There are some great local projects to get involved with, including the HONG KONG MOTHS project and database.