|Lava Reef Zone did not originate from fanon, and more information can be found on their respective wiki(s). You may read more about it on the following wiki(s):|
Lava Reef Zone is a location in the Sonic series. It is the vicinity of a dormant volcano and in Sonic & Knuckles was the landing spot for the Death Egg. It also made an appearance in Sonic Adventure, in which we see the exterior of the volcano, albeit under the name Red Mountain.
Lava Reef Zone also makes an appearance in Sonic Heroes 2. At the end of the game, once the Egg Carrier collapses straight on top of this.