Brazen Bull

The brazen bull is a torture and execution device developed by crafters in Nostauron. It is a hollow bull made of bronze, and portals on its side, where a living person is placed. Bronze tubes inside the cavity carry the heat from a fire built in another part of the bull, and the person slowly roasts to death, as the openings on the animal's head shine with the fire of divine wrath.
It seems that someone was able to animate these devices, and enabled them to remain on fire indefinitely, and to expel it through its nostrils and mouth. The party encountered one such creature outside the cave Under Mount Naos, and managed to subdue it, but later learned from Melas that several other such animated bulls had also escaped, and terrorized the city.