candentidon

30-50 feet in length, size depending on age and sex of the specimen.

apex predator of the old swamp.

a pseudo-wyvern in appearance, candentidon is pitch black, almost tar-like save for the bioluminescent markings that cover its body.
a typical build of a wyvern with its similar theropod-like appearance, there a few key details to this creature that set it apart, and draw confusion of its origin.

firstly is its general body plan and unique method of hunting. aside from its otherwise generic build for its species, the creature has a unique type of skin that allows it to change color and pattern, similar to that of a cuttlefish or squid. being extremely dark normally means candentidon has the advantage as a nocturnal predator, being able to not only blend in but also trick unsuspecting prey by hypnotizing it with a bioluminescent lightshow. 

an extremely aggressive and territorial creature, it has become a danger for travelers and small villages in the area. another odd trait is its wings, or rather lack of them. although candentidon still possesses wingarms, they are smaller and overall stunted compared to other wyverns, having no use in a boggy swamp. instead it uses its powerful wingarm muscles as strength to pounce hypnotized prey, holding it down before clamping on their necks. typically hunts by immersing itself in shallow swamp water, using its lights to draw prey near the shore. travelers often mistake its lights for fish or bugs, leading to common attacks before the creature was identified.