Song of the Symbi is a one-page "spear & planet" roleplaying game based on the equally minimalistic Searchers of the Unknown and inspired by James Cameron's Avatar film. Set on a planet covered with a thick nutrient-rich fluid, the Symbi are orange-speckled green humanoids who were created as part of aborted terraforming project by long-departed humans. The PCs are a group of young warriors who are undertaking dangerous tasks for the tribal elders as part of their rite of passage. Young warriors become elders when they reach 4th level, and increasing in level is based on the number of characters to survive each mission.

Characters have to roll each morning to see if their density has changed; less dense Symbi have a greater empathy, while the more dense are physically powerful. Attacks are resolved by attempting to roll under level opponents AC using 2d6. Snake eyes or doubles are kills, while any other successful hit is a wound (which can be healed by resting overnight in a nutrient pool). Stunts and stealthy actions are resolved by rolling under a character's own AC using 2d6, with modifiers based on terrain and density. Empathic powers allow characters to avoid notice and sense emotions. There are tables for random terrain while traveling, and random encounters.