Anti-Dalek Fluid Gun

A handheld device was in the possession of a tourist visiting the Dalek Dome. When some of the Daleks escaped the simulation, they believed it to be part of the act, and held the device to the Supreme Dalek, asking it to exterminate them, with the Fourteenth Doctor insisting that it wasn't an act, and pulling them away from the Daleks. (COMIC: Liberation of the Daleks)

Behind the scenes
Although not explicitly identified within the narrative, the device can be recognised as a counterpart of the real-world "Dr. Who's Anti-Dalek Fluid Neutraliser" - a water pistol.