Strange Insect spotted at Night Safari

Saw a strange insect crawling its way across a walkway at the Night Safari last Thursday. Wonder what is this insect. I immediately blocked the way and waited until it crossed the walkway so as to prevent people from stepping onto it. It's really a long wait as it really crawled very slow.

After confirmed by Ming and Luan Keng, and also my friend Peiting, it's a Pill Millipede. Pill millipedes are short compared to other millipedes, with only eleven to thirteen body segments, and are capable of rolling into a ball when disturbed. This ability may however have evolved separately in each of the two orders, making it a case of parallel evolution, rather than homology. Pill millipedes are herbivorous, feeding on decomposing plant matter.