In use since at least 1572, probably earlier
Blazon: Gules a demi-dragon rampant or
The House of Boncompagni originated in Umbria, but moved to Bologna in the early 14th century. The family produced one Pope, Gregory XIII, who often incorporated the dragon motif into building projects he commissioned. In 1579, he purchased the Duchy of Sora and granted it to his family. They still retain possession of it today, albeit as an honorary title.
You know, there are really not enough dragons in heraldry. It’s always lions. I mean, lions are also cool, but just look at this shit! I know absolutely nothing about when or why the Boncompagni family decided to use a dragon in their coat of arms, but I wholeheartedly support their decision. MORE DRAGONS.