From the Super Mario Wiki
Retrieved from "https://www.mariowiki.com/index.php?title=Skybridge&oldid=2800690"
The Skybridge is an outdoor area inside of the Haunted Towers in Luigi's Mansion: Dark Moon. The Skybridge can be accessed by taking the east door on the second floor of the Tower Lobby. The Skybridge, as the name states, is a long, wooden bridge that overlooks the Hollow Tree. There are two holes in the sides of the bridge. The door on the left takes Luigi back to the Tower Lobby while the door on the right takes him to the Laboratories.
During A Job for a Plumber, Luigi needs to cross the Skybridge in order to get to the Laboratories. During this mission, a swarm of crows are flying through the holes of the bridge and damage Luigi if he comes in contact with them. These crows can be defeated with the Strobulb, but they yield no money and constantly respawn. In The Pinwheel Gate, Luigi does not have to go to the Skybridge, but the swarm of crows are still present. In Graveyard Shift, along with the swarm of crows, the Skybridge has three Orange Flowers that crush Luigi if he gets too close. In Pool Party, the swarm of crows are no longer there, but the three Orange Flowers still remain. When Luigi visits the Skybridge in this mission, he can hear ghost voices and spooky music.
Only during Pool Party and Hostile Intrusion, Luigi should go to the Skybridge and rip out the Orange Flower to the far right by the door to the Laboratories. This flower drops an emerald for defeating it.