What are 'Siddhis' and how does Chapter 10 connect them to Baba's ability to sleep on the suspended plank?

In the context of Chapter 10, 'Siddhis' are great supernatural or mystical powers. The chapter directly attributes Sai Baba's ability to sleep on the narrow, rag-suspended plank to these powers. It questions how such a flimsy plank, tied with rags, could possibly support his weight, and concludes that with 'Great Siddhis residing within Him, the plank was merely for name’s sake.' This implies that his powers, not the physical plank, were what held him up. The text provides a specific example by mentioning 'Anima,' the power to become minute. It suggests that Baba's movements were so easy and imperceptible because he could take forms as tiny as flies, insects, or ants, which explains why no one ever saw him get on or off the plank.