The Reef used to be a frequently used structure, specifically made for the use of Pearl creation, repair, and modification. The structure is equipped with an Artificial Intelligence named Shell, which assists the user in activating the building's functions.
The Reef has an ocean motif. The building is shaped like a clamshell and it is located on an island in the middle of an ocean. Outside the building's door is a bridge, that connects the island to an unknown piece of land. On the inside, it includes, but is not limited to, an activation room (as shown when Steven places his hand on a Gem Pedestal), a Pearl "remodeling" room, and a Pearl repair room.
Shell, The Reef's built-in A.I., is a helpful guide that makes suggestions as visitors travel throughout the structure. While Steven, Pearl, and Pink Pearl attempt to fix Pink Pearl's scar, Shell states that Pearl and Pink Pearl need to be rejuvenated. This dire situation causes the two Pearls to fuse, forming Mega Pearl. Shell is voiced by Deedee Magno-Hall.
- The clamshell-like design of the building and the fact that it is surrounded by ocean mirrors how Pearls are created in real life (from oysters found in the ocean).
- The seemingly peaceful A.I. that turns out to be "evil and murderous" in the end, along with the walls forming in the objectification hallway and Mega Pearl having to create a series of "holes" on said walls for Steven to pass through may be a reference to the video game, Portal.