Glowing Muck originated when a major chemical cascade at hole 5 spilled mutagenic compounds into a natural swamp on the course, where the toxins fused with organic matter and laboratory waste. The mixture gradually coalesced into a sentient ooze, fueled by residual energy from the facility's failing power systems. This entity now roams the fairways as a living testament to the laboratory's catastrophic failures.

Glowing Muck is composed of viscous, radioactive ooze that emits a pulsating green glow, capable of shape-shifting to navigate obstacles and absorb surrounding contamination. It exhibits corrosive properties, dissolving materials on contact and leaving hazardous residues that persist for hours. The entity is highly adaptable, merging with toxic pools and electrical surges to enhance its mobility and threat level. Its unstable chemical makeup makes it resistant to physical damage, requiring specialized tactics to evade or neutralize.

Glowing Muck acts as a mobile environmental hazard that blocks key fairways and spreads contamination, forcing players to reroute and avoid its toxic presence. It interacts with other experiments to amplify the laboratory's decay, accelerating the narrative toward total breach and escape.