The Scary Collection

There are five dragons also in The Scary Collection:
Dark Dragon    
Vampire Dragon
Pirate Dragon
Zombie Dragon
Rattlesnake Dragon

Now, Dark Dragon is Generation I but you have to be on level 22 before you can get it, and then you probably should buy it.
It takes 12 hours to breed it and 12 hours to hatch it.

Vampire Dragon = Flame + Dark
breeding time 16 hours
hatching time 16 hours

Pirate Dragon = Sea + Dark
breeding time 15 hours
hatching time 15 hours

Zombie Dragon = Metal + Dark
breeding time 12 hours
hatching time 12 hours

Rattlesnake Dragon = Dark + Nature
breeding time 12 hours
hatching time 12 hours

This is a relatively easy collection to collect.