Threat Level
Threat Levels are an indicator in the PDA, located in the Databank. They are used to indicate the how dangerous a specific flora or fauna is to the player when they are close enough to interact with them.
The threat level is determined on a scale from the least dangerous (green) to most dangerous (red). However, the exact criteria used to evaluate a particular flora's or fauna's threat level is unknown.
Most passive fauna (except the Warper) have a threat level of zero. The Reaper Leviathan, Ghost Leviathan, and Sea Dragon Leviathan are the only creatures to have a threat level of maximum. Defensive creatures have anywhere from a low to medium threat level.
The Warper is the only creature that has an unknown threat level.