Dreamy Luigi's abilities in the 2-D levels on the Dream World consist of jumping and activating the Luiginary Works, which are special objects found in the Dream World. When Dreamy Luigi is near a Luiginary Work, both react to each other, causing them to be surrounded by a green light. Dreamy Luigi can "possess" it, creating a special object that can be controlled by the sleepy Luigi with Starlow's help.
In battle, Dreamy Luigi "zooms" into Mario and boosts his HP by 50% and his BP by 20%, regardless of Luigi's stats; he additionally gives Mario they power to spawn multiple copies of him, called Luiginoids. When Mario uses his 'basic' jump attack, multiple Luiginoids appear and jump on any enemies near the initial target. When using the hammer attack, Mario spawns a group of Luiginoids, who then hammer the ground to create a shockwave that hits all grounded enemies, doing more damage the closer they are to the center.
Dreamy Luigi is much like the regular Luigi; he's cowardly and clumsy, but sweet, brave, and loyal to Mario. He seems much more brave in the dream world; Dreamy Luigi is manifested from not only Luigi's dreams, but his emotions and love for his brother, and is always willing to help him out despite the danger, which is demonstrated by his ability to transform into Giant Dreamy Luigi.
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