The Plant Laboratory is an area accessible from the hidden door in Lullaby Land.
Features
This large area is made up of many industrial rooms overgrown with plants. Large colorful flowers can be seen growing in nearly every room, as well as benches that can be sat on. There are various rooms of interest, such as a room with yellow flowers arranged in the Totsu symbol, a room with an entrance that is currently blocked off, and a room with a barefoot NPC in a white gown named Anesi. Attempting to attack Anesi with the Lily of the Valley will result in them unequipping your effect. Deep in the laboratory is a narrow hallway leading to a room with a large sunflower. Interacting with it will give you the Sunflower effect.
Directions
Totsutsuki's Nexus → Lullaby Land → Plant Laboratory