A submarine volcano 800 meters high emerged from the depths of the Indian Ocean in 2018, several tens of kilometers from Mayotte, without any scientists witnessing its birth. Located 50 kilometers east of the island of Mayotte, the Fani Maoré rises 800 meters above the seabed, which is 3,500 meters below sea level. It took until May 2019, a year after the first signs, for France to discover that a new geological structure had emerged on its territory. During this time, the island itself was sinking, without anyone fully understanding why. A series of 1,800 earthquakes struck the island between May 2018 and May 2019, with a quake of magnitude 5.8. The island of Mayotte sank 15 centimeters and shifted 18 centimeters east due to a magma drainage. The seismic sequence in Mayotte began on May 10, 2018, 50-60 kilometers east of Mamoudzou. Five days later, on May 15, 2018, a magnitude 5.8 earthquake struck the entire island: it is the most significant earthquake ever recorded in the Comoros archipelago. Since May 2018, the island of Mayotte has been hit by a swarm of earthquakes, with more than 1,800 tremors felt, with magnitudes above 3.5. Due to the lack of seismic standard structures, some residents prefer to spend the night outdoors, on public squares, out of fear that their roofs might collapse. The ground, however, continues to shake. The volcano emerged without anyone seeing its birth. It took a full year before anyone understood where these repeated tremors were coming from. In May 2019, the scientific campaign MAYOBS revealed the existence of an 800-meter-high volcano located 50 km east of Mayotte, at a depth of 3,500 meters, formed in less than a year from a base of 4 to 5 kilometers in diameter. When discovered in 2019, the volcano had no name. It was finally named Fani Maoré by official, scientific, and journalistic sources since 2022. In 2018, a submarine volcanic eruption, one of the largest ever recorded, shook the island of Mayotte. Faced with the scale of the phenomenon, the French government mobilized the CNRS, the BRGM, the IPGP, Ifremer, and several other research institutes to understand what was happening at the bottom of the ocean. The mystery, finally, has a face. Mayotte slides and sinks, slowly but surely. The island itself was not stationary during the crisis. The IGN noted that the island was moving east at a speed of 14 mm per month, while slightly subsiding. This movement, imperceptible in daily life, accumulates month after month until it becomes measurable to the naked eye along the coastline. In October 2019, the observed sinking of Mayotte due to the phenomenon of magma drainage reached 15 centimeters, causing the beginning of flooding of the residences closest to the shore. The data available at the time indicated 15 centimeters of sinking and 18 centimeters of eastward displacement. Physicist Nathalie Feuillet summarizes the phenomenon with a vivid image: "the island of Mayotte is sitting on a magma pocket that is emptying." To monitor such events in the future, the volcanic and seismic monitoring network of Mayotte, REVOSIMA, was established. Mayotte had never moved so much before. A DOM-TOM under surveillance, finally. In 1963, the volcanic island of Surtsey emerged off the coast of Iceland under the gaze of cameras around the world. Off the coast of Mayotte, nothing comparable: the structure was built under 3,500 meters of water, far from any gaze, before being discovered almost by chance during an oceanographic campaign. Since 2023, contributions from the relevant ministries have increased significantly, indicating the attention now given by public authorities to this unique phenomenon. Since the end of 2020, no movement has been recorded, indicating that the magma pocket under the island has temporarily stabilized. The volcanic and seismic monitoring network of Mayotte remains in charge of monitoring it, in case the Mahorais subsurface decides, one day, to resume its activity.