Hideous Zippleback

 Description:

 Of all the dragons that inhabit the world, one of the most unusual and dangerous is the Hideous Zippleback. The Zippleback is one of the largest dragons you may encounter. It's unmistakable, with its twin heads. The heads are distinct, with separate thoughts and different personalities. Like most dragons, Zipplebacks can fly, but their wings are small, and they spend most of their time on the ground. Zipplebacks are solitary, preferring to hunt alone. They come out after sundown, prowling dark forests for victims. The attack of the Zippleback is like no other. Instead of breathing fire, a Zippel makes explosions. One head breathes gas, and the other head...lights it.
  

Personality:

This evasive, devious dragon can be a very slithery and tricky opponent. Its two heads can work in tandem (when they want to), to outsmart and attack any foe.

HAH! Factor:

The two heads are distinct and do not share thoughts. When arguing with itself, the entire beast can stall out, making it completely vulnerable to attack.

AHH! Factor:

One head produces gas while the other creates a spark. When the two heads combine, it creates a massive explosion of fire.