Abstract: A vessel including a first container having a bottom portion, a sidewall, and a first cavity access portion, wherein one of the at least one sidewalls includes a first region and a second region opposed to the first region, wherein the second region of the sidewall is contiguously joined to the bottom portion to define at least in part a first cavity, and wherein the first region includes a first cavity access opening that is configured to engage the first cavity access portion; and a second container having a bottom portion, a sidewall, and a second cavity access portion, wherein one of the at least one sidewall includes a first region and a second region opposed to the first region; wherein the first cavity is larger than the second container such that the second container may be completely contained within the first cavity.