The Mushroom Forest (キノコの森 Kinoko no Mori), also known as Mushroom Rocks (キノコロックス Kinoko Rokkusu), is an area in the Diablo Desert that has a large amount of vegetation, primarily giant mushroom trees.
It is an area visited in Dragon Ball: Dragon Daihikyou. In Dragon Ball: Origins, it is a stage where Goku must look for Monster Carrot's Hideout and then defeat a T-Rex. It is also where he found the "Curvy Lady" he brought to Master Roshi. In the bonus level 5-6 in this video game, Nam was seeking food for his village after the 21st World Martial Arts Tournament when he ate a mushroom from this forest that made him unbearable; Goku must defeat Nam to reason him after he found him in Monster Carrot's Hideout.
In Dragon Ball Online, this area is called Mushroom Rocks. It was taken over by the Paella Gang in Age 988. Mushroom Rocks is separated into two areas, called Mushroom Rocks North and Mushroom Rocks South. Mushroom Rocks North resembles the area's appearance in the show, while the ground in Mushroom Rocks south is reddish in coloration. Pilaf's Castle is located on the border between the two areas.
Mushroom Rocks south contains the Isuri Area, which is home to Isuri's Lake and Naraku's Footprint. Isuri's Lake being the place where King Piccolo was sealed and where his throne was located, the Namekians who settled here ended up becoming the Dark Namekians.