Your snake pooped then the sand in his cage was all wet did he pee too?
Snakes, including corn snakes, do not have bladders and, therefore, do not produce urine. Excess water from food and liquid consumption is released through their skin rather than through urination. They do, however, produce a different kind of waste called urates. Urates are a whitish or yellowish substance that is semi-solid and chalky in texture. Snakes generally excrete urates separately from their feces.