Named and Unnamed
Nebuchadnezzar's (unnamed) dragon was sometimes referred to as Bel.  It could be that translators conflated the story of Daniel's destruction of the idol Bel with his subsequent slaying of the deified, but unnamed, dragon in The Book of Daniel.
However, the Akkadian word Bel means 'Master,' and it became the component of several divine names in the mythology and religion of Mesopotamia.  So it is also possible that other accounts attribute the name Bel to the dragon in order to establish its divinity.
Nebuchadnezzar's Dragon, or Bel, was described in the Book of Daniel in the Old Testament of the Bible.  Daniel, the son of Habal, was a prophet and wise man who was known for his ability to interpret dreams.  He was a captive companion to King Nebuchadnezzar. 
At the same time in Babylon, there existed a terrible dragon revered and honored in Babylon. Nebuchadnezzar called Daniel to answer for his lack of deference towards a living deity. Daniel asked permission to defeat the dragon. 
'Give me permission, O king, and I will kill this dragon without sword or club.'
-- Daniel 14:26 
Thus, Daniel took pitch, fat, and hair and boiled it together into a cake. Then he threw it into the mouth of the beast, and once the dragon swallowed, it burst apart.  Standing over the remains of the beast, Daniel asked, "Aren't these the things you revere, O king?" 
While Bel was not described specifically, it probably took a form similar to Sirrush (or Mushussu), the Dragon of Ishtar Gate. Thus, Bel probably had the body of a lizard, the hind limbs of an eagle, forelimbs of a lion, and the head of a serpent topped with horrible horns. 
- Bel was name sometimes used to refer to Nebuchadnezzar's dragon. 
- He was a terrible dragon, revered and honored throughout Babylon. 
- Upon Nebuchadnezzar's challenge, the prophet Daniel slew Bel. 
- Bel ate a cake made of pitch, fat, and hair when Daniel threw it into his mouth. Once he swallowed it, Bel burst apart. 
- The dragon Bel had a lizard body, hind limbs of an eagle, lion forelimbs, and a serpent head.