Spelljammer is a unique campaign setting in the Dungeons & Dragons universe that combines fantasy with space travel. In this setting, magical ships called spelljammers traverse the vastness of the Phlogiston, a colorful, ethereal sea that connects various worlds and realms. Adventurers can explore diverse planets, each with its own cultures, creatures, and challenges. The setting allows for imaginative storytelling, where players can encounter various fantasy races and engage in epic space battles, all while utilizing the power of magic to navigate the cosmos.