The Moon Grotto is an area in Nibel. It is located below Thornfelt Swamp.
Ori and the Blind Forest/Definitive Edition
Moon Grotto is first introduced while chasing Gumo, marked by the large letters, the lasers, and the change in music, switching to a sad clarinet tune. The spikes here will often hurt a lot, taking up to three lives. Moon Grotto is also quite hard in general, with many secrets and side paths.
Sub-Area: Gumo's Hideout
Gumo's Hideout is an area in Nibel where Gumo lives. It is a dark cave with glowing mushrooms, roots, and waterfalls, and contains many moving contraptions such as moving pillars and spikes (possibly made by Gumo). The area contains Leru's Ancestral Tree, which gives Ori the ability to Double Jump. It also contains the first "mid-boss" fight and a sequence involving a rock slide.
Ori and the Blind Forest
Gumo lived in his hideout during the time that the forest was blind. When he obtained the Water Vein at the Ginso Tree and was seen by Ori, he ran with the orb to his hideout while Ori chaseed after him. When Ori reached the bridge right above Gumo's hideout, Gumo activated the bridge trap, sending Ori down to the bottom of his hideout.
Ori evaded many contraptions and traps as Gumo ran from them, activating traps along the way. At the last trap, Gumo attempted to pull the lever to activate a rock slide, but the force of pulling the lever knocked him off backwards and hit a wooden pillar behind him, causing a boulder to trap him at his feet. As Ori dodged through the rock slide trap and finally reached Gumo, the spirit showed kindness by freeing him from the boulder. Gumo apologized by giving Ori the Water Vein.