We propose the demonstration of CLASH, a high-level abstraction on top of Apache Storm. CLASH is designed around MultiStream, a novel join operator designed for native support of distributed, multi-way stream joins. MultiStream allows trading off materialization of intermediate results versus communication load. With this demonstration, we invite the audience to explore the full potential of CLASH: multi-way stream joins, creation of complex join plans and their automated optimization, and ultimately the hassle-free SQL-style user/application interface and the translation of the optimized query plans to deployable Storm topologies that are executed on our local compute cluster.