Uncontained Magma is the 17th cargo you unlock and can damage your boat if it isn't contained properly. It gives 20,000 coins and 31 gems each time it passes the end of a map.
Containment[]
The Uncontained Magma burns surrounding blocks, the only block that doesn't get burned by this cargo is obsidian, surround your Uncontained Magma with obsidian to keep the rest of your boat safe.
Obsidian Spikes also work.
Appearance[]
The Uncontained Magma has a neon orange interior with a translucent pebble exterior, the cargo also emits a red fire-like particle.