The Volcano is a location that appeared in Battle for Dream Island. It is the area where the 23rd contest took place, in Don't Pierce My Flesh. It also reappeared in Hurtful! as the last challenge to recap.
The Volcano first appeared in Don't Pierce My Flesh, where the final 5 contestants had to escape it. Eventually, they all fail the challenge as the volcano erupted. Flower and Firey were given immunity thanks to the speaker boxes that they made, and Spongy, Bubble, and Leafy were up for elimination.
In Hurtful!, Bubble makes it to the volcano, and so does everyone else. Leafy says that Bubble should win the contest, but Bubble says "no thanks", saying that it's not fun when Leafy always lets her win. Leafy gets offended, and she says that she's a bad friend, and Flower would like her more. Flower interjects and adds fuel to the flaming conversation between Leafy and Bubble. Leafy says her friendship with Bubble is over. Flower moves into, and pushes Leafy into the lava, saying thier friendship had begun. Bubble throws Flower into the magma, Bubble creates another pole, and she wins immunity, saying an ecstatic "Yoylecake!" at the summit.
While it didn't reappear since season 1, a lava river was shown in Getting Teardrop to Talk. It is possible that The Volcano was a source of the lava.