Solid vessels are robust but are difficult to remove and re-form. Liquid walls are adaptive and self-healable, but complex system designs or pre-treatments are usually needed for controlling the shape of liquid walls. Here, we describe the fabrication of free-standing and erasable polymer hydrogel walls with desired shapes in a facile manner. We fabricated a series of metal-coordinating polymer hydrogels with controllable rheological properties. Systematic studies to investigate the interfacial behaviors between the hydrogels and solid substrates (e.g., poly(tetrafluoroethylene), polyvinyl chloride, and quartz) or confined liquids (e.g., n-hexadecane, nonane, toluene, and 1-nonanol) were performed, and the optimized hydrogels displayed excellent performance to serve as hydrogel wells to confine non-polar and weakly polar liquids. The success in hydrogel-templated polymerization demonstrated the potential application of the hydrogel wells as reaction vessels and verified the importance of easily erasable properties of the reaction vessels. The shape-controllable polymer hydrogel wells have the advantages of both solid and liquid vessels, they are free-standing, simply erasable, and multifunctional, making them potentially useful as transient reaction vessels.