Bowser Jr.'s Lava Reactor is a Bowser galaxy in Super Mario Galaxy. It is named due to its high lava content. King Kaliente makes his second appearance here. Mario can access this galaxy when he gets 45 Power Stars in his possession, including the Grand Stars from the Gateway Galaxy, Bowser Jr.'s Robot Reactor, Bowser's Star Reactor, Bowser Jr.'s Airship Armada, and Bowser's Dark Matter Plant. The icon representing the Galaxy is the reactor itself and the deteriorating Starting Planet (without the Black Hole).


King Kaliente's Spicy Return

Mario must defeat King Kaliente once again to get a Grand Star.


Starting Planet

This spherical dirt ball has been devoured nearly completely by a black hole that somehow reached the planet's core and is absent in the icon. Goombas and Bill Blasters can be found here.

Lava Reactor

This star-like entity is very large, taking up most of the galaxy. It bears some resemblance to the planet Solar from the Star Fox series. Its northern half holds King Kaliente, while the southern half contains a few sinking platforms in a path that can somehow withstand the lava.

Background Star

There is a bright white star that cannot be reached, far out from the galaxy's main regions. It looks very much like the sun.


  • This is the only galaxy that does not have any skyboxes at all. Looking around, you see a black void.
    • Bowser Jr.'s Lava Reactor is also the only boss galaxy in the entire series to have this trait. Most of Bowser Jr.'s galaxies involve blue planets in the background with a starry sky.
    • This, combined with the fact that King Kaliente has his color changed to a darker hue, may have been done to give the level a vibe of unease and/or horror.
    • Even the Matter Splatter Galaxy has a skybox, albeit one that does not envelop the entire galaxy.

Names In Other Languages

  • Japanese: Kuppa Jr. Kurīchā Puranto (Bowser Jr.'s Creature Plant)
  • Spanish: La Dimensión Bowsius Y Suro Soldadoro (Bowser Jr. & His Army's Dimension ("Bowsy" is Bowser Jr.'s Spanish name.))
  • Italian: Il Mondo Torrido Bowserus Giuniorus (Bowser Jr.'s Torrid World)
  • Portuguese: A Dimensão Kuppes Juniorus (Bowser Jr.'s Dimension)
  • French: L'Usine de créatures Bowsere-osse Juniore-osse (Bowser Jr.'s Creature Plant)