Archer Maclean's Mercury is a 2005 puzzle-platform video game developed by British company Awesome Studios and published by Ignition Entertainment for the PlayStation Portable. It was conceptualized by the eponymous British game programmer Archer Maclean. Sony Computer Entertainment released the game in Japan as [Hg] Hydride.

In Mercury, the goal is to guide a drop of mercury to its appointed destination by tilting the stage, in a similar fashion to Super Monkey Ball. Levels come in different varieties that prioritize different methods of completing each level. The game was conceived when Archer Maclean used a previous minigame from Jimmy White's Cueball World and added a liquid metal physics. It was originally designed to have motion controls by using a tilt sensor peripheral for the PSP, but this version was never released due to technical constraints.

The game had received positive reception for its original concept and level designs but had received mixed reception for its difficulty. The game's success led to receiving two sequels. The first, titled Mercury Meltdown, was released for PSP, then revised and ported onto PlayStation 2 and Wii. The second sequel, titled Mercury Hg, was released for PlayStation 3 and Xbox 360.