Petrolwyrm

big reptile things! They live near oil resevoirs underground, they're long & thin, almost snake like in body shape, and they excrete a kind of oil that helps them squeeze through narrow passages. The hide, if taken off of them, still retains this quality. Their breath weapon is also an oil/grease analog with 2 variants: they can either shoot it to ensnare/bind targets, or slick them up like a grease spell. Whatever organ they use for this is probably valuable for some use, especially if people get creative with it? The meat from them is borderline inedible, though, since it tends to not, uh, stop cooking when it's lit :joy: They don't have wings, but can cling to walls and ceilings, as well as have excellent traction on difficult surfaces. They can breathe in water and oil (and have whatever other capabilities needed to survive those conditions).   Finally, at the bottom of the oil reservoirs they frequent, I'd like to make these perfectly round black gems that slowly (over decades) grow over time (I'm jokingly calling them pearl-trolium). The dragons innately want to collect these! Idk what exactly they do, but probably helping to make magic items or enchant things!   All natural oil and gas in this world is produced by these reptiles.