The Fire Dragon is a fire-breathing monster that lives in the Desert of Tropica. It encounters Flash, Zarkov, Dale and Queen Desira but is killed by Flash and Zarkov using ray-pistols.
In the 1936 serial it is a sacred creature who lives in the Tunnel of Terror on Mongo, guarding the temple of the Great God Tao.
Dr. Hans Zarkov blows its head off with a grenade. ("Chapter 110: The Unseen Peril")
This earns him the wrath of the High Priest.