The search and rescue of refugees, asylum seekers and migrants on the Mediterranean has become a site of major political contestation in Europe, on the seas, in parliaments and government offices and in online public opinion. This article summarises one particular set of controversies, namely, false claims that the non-government organisations conducting such search and rescue operations are actively ‘colluding’ with people smugglers to ferry people into Europe. In spring and summer 2017, these claims of ‘collusion’ emerged from state agencies and from anti-immigration groups, became viral on social media platforms and rapidly moved into mainstream media coverage, criminal investigations by prosecutors and the speech and laws of politicians across the continent. These claims were in turn connected to far-right conspiracy theories about ‘flooding’ Europe with ‘invaders’. By looking at the experience of one particular ship, the MV Aquarius, run in partnership by MSF and SOS Méditerranée, the authors detail the risks that humanitarian organisations now face from such types of disinformation campaign. If humanitarian organisations do not prepare themselves against this risk, they will find themselves in a world turned upside-down, in which their efforts to help people in distress become evidence of criminal activity.