Ultra-dense deuterium D(−1) is expected to be both superfluid and superconductive. It is deposited on surfaces below a novel source producing a stream of D(−1) clusters. It is studied by laser probing and Coulomb explosions giving cluster fragments which are observed by time-of-flight measurements. It is observed on surfaces at a few cm height above the container below the source, and on the outside of the container. D(−1) is detected above a 1 cm long vertical capillary in vacuum (fountain effect). This suggests the existence of superfluid D(−1) which is the only material that may be superfluid at room temperature.