Giant Pill Millipedes (Sphaerotheriida order) are very cute and harmless little arthropods.
They roll into a hard ball as a protection against predators. Normally, they look like this.
If you can identify the exact species of Giant Pill Millipedes (Sphaerotheriida order, Zephroniidae family), please post a comment or email me!
For more information about Sphaerotheriida, read en.wikipedia.org/wiki/Sphaerotheriida
Photo taken in Gunung Mulu National Park (Borneo)