Dragon Hoarding is confusingly two different but related terms:
2. When the Creature doing the Hoarding is actually a Dragon. This is pretty common, in fact, because most Dragons hoard Gold. Many, however, hoard other weird shit.
Dragons are notorious hoarders and will flip the fuck out and burn every motherfucker around if you steal a single bauble from their ridiculous "collections", or if you will; piles and piles of garbage.
Hoarding is a very serious Disorder and should be treated by a medical professional. This is impossible to do for most Dragon sufferers, however, as they will burn every motherfucker around if you confront them about their problem. They are incredibly possessive, to the point of driving all their loved ones and acquaintances away with accusations and burning, and even having paranoid delusions of invisible people sneaking around their cavernous hideaways.
The physical ramifications of hoarding by dragons include filthy disease, torpor, atrophy, and even becoming encrusted in the collectible items themselves.