Woohoo Hooniversity is a major location that appears in Mario & Luigi: Superstar Saga. Originally, it was where the Beanbean scientists go to do research until Cackletta, along with Fawful, planned to use this place to help awaken the Beanstar.
After discovering where Cackletta plans to awaken the Beanstar at, Mario and Luigi head to Woohoo Hooniversity to due battle with the bean witch herself. Mario and Luigi battle through many enemies and puzzles until they reach the room with Cackletta and Fawful in. Cackletta then turns on her Peach Bots to help awaken the Beanstar but the voices only anger the Beanstar causing it to go on a rampage and falls down into the basement. Confused, Cackletta wonders what happen and the Mario Bros. jump into action. They stomp Fawful down and prepare to fight Cackletta. Cackletta is soon defeated and Fawful absorbs her soul. As Fawful is about to attack Mario and Luigi on Cackletta' orders, Prince Peasley suddenly appears and knocks the two away. Prince Peasley then suggests to Mario and Luigi that they should head to the basement to retrieve the Beanstar. Mario and Luigi done so and as they enter the room with the Beanstar in, Popple and Rookie are seen with it. The two teams then get into the battle in which Mario and Luigi eventually win. However, another Peach Bot falls down near the Beanstar and makes more noises causing the Beanstar to grow more angry and bigger in size and starts to fly up. Mario, Luigi, Popple, and Rookie all grab on and crashes through the ceiling (with Bowser gaining back his memories). However, everyone then falls off the Beanstar with Mario and Luigi landing on Oho Oasis, Popple in Chucklehuck Woods, and Bowser in Stardust Fields.
- The asterisk (*) means the enemy can be fought only in the Game Boy and Wii U versions.
- Two asterisks (**) indicate the enemy can be fought only in the 3DS version.
- While Mario was in the basement saving Luigi in the barrel by outwitting barrels sliding, this was possibly referenced Donkey Kong.
- This area is one of the only two areas not explored in the remake's Minion Quest. The only other being Guffawha Ruins.
- This is the only area to get a repopulation of enemies: the Mecha-Chomp only appears in the Game Boy and Wii U versions while the Mechakoopa appears in the 3DS version.