■Petroleum is an oil in real life, used primarily as a fuel source for most combustion engines.
■Its egg shares the same appearance with the Mercury Dragon's Egg, differing only in its colour.
■Its rotund appearance is similar to the Gummy Dragon.
■Its egg is darker than the Dark Dragon's egg, which has spots.
■The Petroleum Dragon was an Rare Hybrid until Light and War upgrade but now its a Hybrid Dragon. It shares this fact with the Pirate Dragon.
■You can get the Pirate Dragon with the same combination of parents