The Koopaseum is a large, Colosseum-like structure in the middle of the Gritzy Desert that appears in Mario & Luigi: Partners in Time. In the past, the Mario brothers and the Baby Mario brothers came to the Koopaseum looking for Princess Peach. Once the brothers entered, they saw Peach being fed to Petey Piranha on Princess Shroob's commands.
In the Koopaseum, the brothers fight Shrooboid Brat in the middle of a stage with millions of Shroobs watching them. Even though the brothers defeat Shrooboid Brat, the brothers are taken down by lots of Shroobs with hammers. The adult and baby Mario brothers are then dropped to Gritzy Caves, which is right below the colosseum.
Items
| Item | Icon | Found In |
|---|---|---|
| Ultra Mushroom | 
|
In the left ? Block in the northwest of the dark room behind the sixth scene. |
| Super Drop | 
|
In the southeast ? Block in the inner room to the east of the second scene. |
| 1-Up Super | 
|
In the northwest red block in the inner room to the east of the second scene. |
| Refreshing Herb | 
|
Two are in the right ? Block above the west platform in the sixth scene. |
| Cannonballer | File:Canonball.PNG | Three are in the left ? Block above the west platform in the sixth scene. |
| Hit-POW Badge | 
|
In the next-to-northwest green block in the inner room to the east of the second scene. |
| Pep Badge |
|
In the red block in the southeast of the dark room behind the sixth scene. |
| Adult Trousers | 
|
In the right red block in the northwest of the dark room behind the sixth scene. |
| Bean | 
|
In the east corner of the second scene. |
| In the southeast of the sixth scene. |
