Hatchling's Hoard is an Advanced Monster Room introduced in the Boss Monster: The Next Level set.
Hatchling's Hoard is possibly one of the more unique Advanced Rooms introduced into Boss Monster, as it can be built over any room. Despite its low power of 2, it is a good card for luring in all types of Heroes. It is essentially a stronger version of Dragon Hatchery, a Monster Room from the Base Set of Boss Monster.
The dragon featured in the artwork is actually a baby Kirax. This same dragon appears on a Spell card called Surprise Gift.