Bali's advisor identified the true identity of Vamana and tried to stop him from granting the wish by shrinking into a minuscule size and lodging himself in the spout of the vessel that Bali was about to use to pour out holy water and seal the promise. Bali mistook the tiny creature as some obstruction and poked him out with a blade of grass which accidentally hurt the advisor's eyes and made him blind in one eye.