Sketched out a puzzle involving several weighted pedestals and a mysterious water basin. The general idea is that each pedestal will fill the basin with a different liquid when activated, and the properties of the liquids are needed to acquire/create/modify certain objects (e.g. turning them to lead, changing their size, etc) to allow for the activation of multiple pedestals simultaneously.
If it works out, it will make for some interesting possibilities in Act III (when the forest becomes available once again).