Bowser Jr.'s Robot Reactor

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Bowser Jr.'s Robot Reactor
Bowser Jr.'s Robot Reactor.png
Area Terrace
How to unlock Get 8 stars
Boss(es) Megaleg
Mission(s) Megaleg's Moon
Music track(s) A Tense Moment
Stars A Grand Star icon from Super Mario Galaxy.
Galaxy icon Bowser's head (before completion)
Megaleg on the Robot Reactor (after completion)
“Wahahaha! You made it! But I won't even need my dad's help to take care of you! Go at 'em, Megaleg! Stomp 'em with the power of your Grand Star!”
Bowser Jr., Super Mario Galaxy

Bowser Jr.'s Robot Reactor is Bowser Jr.'s first galaxy in the game Super Mario Galaxy. In it, Mario fights Megaleg to earn a Grand Star.


NOTE: Unless otherwise marked, all names are unofficial.

Starting Planet[edit]

The start of Bowser Jr.'s Robot Reactor
The Starting Planet

This is a very small planet. Mario is required to entice a Bullet Bill to follow him and break open a cage to reveal a Launch Star, and then use that Launch Star to reach the Robot Reactor. This metal planet has a black hole that Mario needs to avoid. There are also other cages that can be broken to reveal coins or a 1-Up Mushroom. It is also infested with several Goombeetles, which make it slightly harder to traverse the narrow pathways while being pursued by a Bullet Bill. There is an odd shortcut on this planet. If the player Triple Jumps off the cage with the Launch Star and Spin they can reach Megaleg faster.

Robot Reactor[edit]

A screenshot of Bowser Jr.'s Robot Reactor during the "Megaleg's Moon" mission from Super Mario Galaxy.
The Robot Reactor

This is where Megaleg is found and battled. It is fairly small and orange-brown, with many technologic symbols all over it. It has small rectangular areas on it that are transparent and seem to have computer components inside them. Despite Megaleg's probable immense weight, the transparent panels never break if Megaleg stomps on them; all that happens is a cloud of dust rises up. In the underside, there are several glass containers around the back of the planet that can be destroyed with the help of Bullet Bills for items. If players go to Megaleg's back leg, they find a 1-Up Mushroom. The Robot Reactor orbits the starting planet.



This galaxy consists of only the following mission.

Mission Image Summary

Megaleg's Moon The top of Megaleg's head Mario must battle and defeat Megaleg to obtain the Grand Star of the Terrace.


Names in other languages[edit]

Language Name Meaning
Japanese クッパJr.ロボプラント
Kuppa Junia Robo Puranto
Bowser Jr.'s Robo-Plant

Chinese 酷霸王Jr.机器人工厂
Kùbàwáng Jr. jīqìrén gōngchǎng
Bowser Jr.'s Robot Factory

French (NOA) Usine de Robots
Robot Factory
French (NOE) Usine de robots
Robot Factory
German Bowser Jr.s Robofabrik
Bowser Jr.'s Robo-Factory
Italian Robo-Impianto di Bowser Jr.
Bowser Jr.'s Robo-Plant
Korean 쿠파주니어 로봇 플랜트
Kupa Junieo Robot Peullaenteu
Bowser Jr.'s Robot Plant

Spanish (NOA) Dimensión Robot de Bowser Jr.
Bowser Jr.'s Robot Dimension
Spanish (NOE) Dimensión Robot de Bowsy
Bowsy's Robot Dimension
(Bowsy is Bowser Jr.'s Spanish name in Europe)


  • If the player uses the first person view from Megaleg's moon to look at the starting planet, the player will see that it looks like its grassy early appearance, instead of being metallic.