The Czar Dragon is the dragon made out of many Pyrospheres and the boss of the Barrel Volcano, who is guarding the sixth Star Piece in Super Mario RPG: Legend of the Seven Stars. The dragon first appears when a group of Pyrospheres join together to form it, and it immediately attacks the party. The dragon is physically strong and uses a small variety of powerful magic, most notable of them Flame Wall. It will also summon Helio to kamikaze-strike the party, similar to Punchinello. In the end the dragon falls, but promptly rises from the grave as Zombone. Mario and friends must fight an even more difficult battle, but prevail and acquire the Star Piece, only to have it snatched by the Axem Rangers.
"Czar" is a Russian title meaning "Emperor", derived from the title "Caesar" used during the Roman Empire. "Kaiser", the Japanese name for the dragon, comes from the German word for "Emperor", which was also derived from the title of "Caesar". The Czar Dragon resembles the Blargg species from Super Mario World.
In Final Fantasy VI (a game also created by Square), there is an unused enemy known as CzarDragon with an unfinished battle script. It was brought back as the superboss Kaiser Dragon (the Japanese name of both dragons) in Final Fantasy VI Advance, though an exact copy of the the original Kaiser Dragon still exists in the game data. The name of its second form, Zombone, is also derived from Final Fantasy VI.
The rendition of the Czar Dragon in the game intro is internally known as "Magidragon" in the English version, whereas it was blank in the Japanese version.