We present Drile, a multiprocess immersive instrument built uponthe hierarchical live-looping technique and aimed at musical performance. This technique consists in creating musical trees whosenodes are composed of sound effects applied to a musical content.In the leaves, this content is a one-shot sound, whereas in higherlevel nodes this content is composed of live-recorded sequencesof parameters of the children nodes. Drile allows musicians tointeract efficiently with these trees in an immersive environment.Nodes are represented as worms, which are 3D audiovisual objects. Worms can be manipulated using 3D interaction techniques,and several operations can be applied to the live-looping trees. Theenvironment is composed of several virtual rooms, i.e. group oftrees, corresponding to specific sounds and effects. Learning Drileis progressive since the musical control complexity varies according to the levels in live-looping trees. Thus beginners may havelimited control over only root worms while still obtaining musically interesting results. Advanced users may modify the trees andmanipulate each of the worms.