The abbreviation SLI (Street Light Interference) references an urban myth about the erratic behaviour of streetlights apparently caused by one or several individuals. Some see what is no doubt the result of wear or chance as a manifestation of the paranormal. These are the SLIders among us: people capable of using their thought waves to interfere with public lighting. This piece offers the experience of lights possessed by some mysterious entity. These lamps are prepared in order to give the impression that their working is being perturbed by an alien signal, which is deliberately left undefined for the viewer. It could be either a simple technological artefact or a genuine paranormal manifestation. These electrical anomalies are perceived via the flickering of the light but also through buzzing sounds and ghostly human voices. The idea is more to conjure up a presence than to stage a narrative. Ghostly manifestations are related to transcription errors made by analogue technologies for recording the real. Just as they have taken the haziness out of our images, have digital technologies also deprived those ghosts of their sheets? This work offers another solution to these ghosts that no longer exist. Our tampered-with lamps are like the imperfect ventriloquists of a fictive or bygone parallel world.