Alkahest

Alkahest (or alcahest) is a hypothetical universal solvent, having the power to dissolve every other substance, including gold. It was much sought after by alchemists for its invaluable medicinal qualities. The name is believed to have been invented by Paracelsus (1493–1541), who modelled it on similar words taken from Arabic, such as ‘alkali’. Paracelsus' own recipe was based on caustic lime, alcohol, and carbonate of potash.

In fact a universal solvent does not, and cannot, exist. The closest is likely to be aqua regia — or, depending on how one defines “dissolve”, antimatter.