The 29th of May 2006 several gas and mud eruption sites suddenly appeared along a fault in the NE of Java, Indonesia. Within weeks several villages were submerged by boiling mud. The most prominent eruption site was named Lusi. To date Lusi is still active and has forced 50.000 people to be evacuated and an area of more than 7 km2 is covered by mud. The social impact of the eruption and its spectacular dimensions still attract the attention of international media. Since 2006 I have completed four expeditions to Indonesia and initiated quantitative and experimental studies leading to the publication of two papers focussing on the plumbing system and the mechanisms of the Lusi eruption. However still many unanswered questions remain. What lies beneath Lusi? Is Lusi a mud volcano or part of a larger hydrothermal system? What are the mechanisms triggering the eruption? How long will the eruption last?LUSI LAB is an ambitious project that aims to answer these questions and to perform a multidisciplinary study using Lusi as a unique natural laboratory. Due to its relatively easy accessibility, the geological setting, and the vast scale, the Lusi eruption represents an unprecedented opportunity to study and learn from an ongoing active eruptive system. The results will be crucial for understanding focused fluid flow systems in other sedimentary basins world-wide, and to unravel issues related to geohazards and palaeoclimate aspects. The project will use multisensory sampling devices within the active feeder channel and a remote-controlled raft and flying device to access and sample the crater and the erupted gases. UV-gas camera imaging to measure the rate and composition of the erupted gases will be coupled with a network of seismometers to evaluate the impact that seismicity, local faulting and the neighbouring Arjuno-Welirang volcanic complex have on the long-lasting Lusi activity. This information will provide robust constraints to model the pulsating Lusi behaviour.