It was a cool night, and the air was heavy. Crickets chirped, mixing with the sound of flowing water and the rustling leaves that denoted the variety of life in this area. If one were to (unwisely) go deeper into the swamp, they might notice that the sounds started to quiet, eventually leading to a dead silence that coated the part of the waters inhabited by a certain predator.
The rumors, the local legends and tales of missing pets and children, caused most to avoid the territory of the creature that haunted the dark waters of the swamp.
Even well intentioned environmentalists had learned to steer clear, warned off by fishermen local to the area. Signs were posted, alerting tourists to the danger hidden in the murky depths of the otherwise idyllic waters.
Not all supernatural creatures had the temperament for coexisting with humans, regardless of what the laws might say.
Angui was a solitary creature. He defied taxonomy; his closest kin were merfolk, or perhaps hydras. The locals simply called him the swamp thing.
Angui preferred not to be referred to, or spoken to, at all.
Thus, when splashing disturbed the peace of his territory, Angui cut through the water, eel-like. He was not hunting, not yet anyway. When he saw the disturbance - humanoid, drowning - he dove deeper, surprisingly strong arms lifting the intruder out of the water and depositing them on a nearby, half-rotted dock.
Then he retreats to a safe distance, low in the water, luminescent yellow eyes and lanky dark hair the only features visible. Then he speaks. The voice is rough, hoarse from disuse, a whisper in the reeds.
"φύγε. (Go away.)"