Enzyme 42

Enzyme 42 is an enzyme found in almost every life form on Planet 4546B but is only produced by the Sea Emperor Leviathan and Sea Emperor Babies. It is the only known cure for Carar. The Precursors were investigating how to produce a cure using Enzyme 42. Peepers using the Alien Pipe System carry small amounts of the enzyme, having contracted it from the captive Sea Emperor Leviathan, distributing it throughout the planet.

The Sea Emperor Leviathan occasionally releases Enzyme 42 as a cloud whilst it swims around the aquarium, the Babies release it as a solid ball of concentrated Enzyme 42. This may reflect the unstable nature of the captive's Enzyme.

Trivia

 * The name might be a reference to Douglas Adams' The Hitchhiker's Guide to the Galaxy, where 42 is the answer to the Ultimate Question of Life, the Universe, and Everything.