When Vali awoke, he made his way to the cave entrance, only to discover a huge boulder blocking his path. Vali smashed the boulder and rushed to the palace, where he found Sugriva on the throne. Enraged, Vali attacked Sugriva, and Sugriva fled to the only place of safety he could think of: the ashram of Sage Matanga, which Vali dared not enter.
Inspired by: Sita: An Illustrated Retelling of the Ramayana by Devdutt Pattanaik
Notes: This story is on p. 155 of the book. In Valmiki's Ramayana, this is the Kishkindha Kanda (Book 4), sarga 9.