Baron Brr is a boss in Super Mario Galaxy appearing on Freezeflame Galaxy. It is presumed he is the leader of Brrr Bits. He resembles Chief Chilly and Crystal King. The Freezeflame Galaxy is the only galaxy he appears in.
Baron Brr makes his first appearance in the mission intro, which shows the camera panning up his home planet until it reaches the boss himself.
Baron Brr is fought after Mario makes his way halfway up the snowy mountain during the first mission "The Frozen Peak of Baron Brr." From a distance, Baron Brr will shoot chunks of ice at Mario that could damage him. When Mario is up close, Baron Brr will crash onto the platform and send out shockwaves that could knock Mario off the platform and into the icy-cold water.
In order to reach Baron Brr, Mario must grab an Ice Flower to become Ice Mario and skate his way across the icy water and Wall Jump up to Baron Brr. Mario should carefully jump over the shockwaves and attack Baron Brr with a Spin. After Baron Brr has been hit, he will attempt to get back his icy armor by rolling around in the snow. This is Mario's chance to use another Spin attack to effectively damage Baron Brr. If Mario repeats this process two more times, Baron Brr will be destroyed. Mario is awarded with a Power Star.
- Due to his death in the first game, Baron Brr does not appear in the sequel. However, his battle theme is remixed when Mario fights King Lakitu and the Stink Bug Parent.
- Even though "The Frozen Peak of Baron Brr" is the first mission, Mario can actually ignore the fight with Baron Brr and go to the other side of the mountain to complete the sixth mission "Conquering the Summit" first.
- Baron Brr's name is based on the 3rd vice president of the United States Aaron Burr.
- His battle theme is reused when you fight the Undergrunt Gunner in the Deep Dark Galaxy.