- "First I had to turn into Grey Matter to figure all this out. Next, I turned into Armodrillo to make all this space and the riverbed. Once that was all set up, I used Upchuck to clear out any leftover chunks of rock and turn them into nutrients for the sand. Thanks to the nutrients, the ground became perfectly good soil. Following that, I used Water Hazard to fill the the place up with water. With the water done, I used my plant guys to grow the plants. Not only do they provide food, they also provide good structural support. Afterwards, I was able to use Lodestar to luckily find some iron filled metal, which I then magnetized. Next, I had Upgrade mold the metal into a self-sufficient irrigation system and water recycling device. As soon as I was done there, I used Water Hazard again to replace the water that been used up by the plants. Ha! Here everyone thought I never payed any attention in class. While I was Grey Matter, I figured that, as long as the food is properly rationed, this stuff could feed over a dozen Hollows daily, providing them with something else to eat besides souls. "
- ―Ben Tennyson explaining how and why he created the Oasis[src]
The Oasis bears a slight resemblance to the biblical Garden of Eden, minus the animals. It is composed of various fruit trees and vegetable gardens, all of which are kept irrigated by a water system that is fueled by reiatsu. The central power generator of the Oasis is a crystal from Chromastone, which is itself powered by a Cero. The more powerful the Cero used, the longer the Oasis is sustained.
The fruits and vegetables in the Oasis are filled with reishi, thus anyone who eats them will be filled with it. According to Ben, the Oasis in its current state could easily feed a dozen Hollows.
The Oasis was created by Ben Tennyson in the finale of the Have Time, Will Travel arc. Using many complicated steps and methods involving his alien forms, all of them being strengthened by the Hogyoku, Ben converted a small cave into a large paradise.
The first thing Ben did was show his creation to then Vasto Lorde Tia Harribel and her future Fraccion - Apacci Emilou, Sung-Sun, and Mila Rose, all three of whom were Adjuchas at the time. The four were amazed by what they saw and, upon sampling the fruits and vegetables (and using Ceros to power the crystal), swore allegiance to Ben in gratitude for all he had done for them.