King Boo can create storms capable of producing lightning, although the latter part is nothing new. He also can extend his tongue out super far and use it as a weapon. He can produce fireballs, and the big one, can duplicate himself as much as three times that all can perform the same attacks. Granted, these duplicates seem to not have any mass as they don't produce shockwaves when slamming into the ground and will poof awau should the main King Boo be attacked. Also direct showings of telekinesis, size manipulation from the frame he grows to larger than the hotel, and he can produce bombs like the Boos so it's also quite likely he can summon bats as well. It should alsl be worth noting that Luigi's lights do absolutely nothing to the guy. Most bosses, NPCs, and enemies react in some way to the light (some even reacting in time to block and/ir reflect it) and Boos are susceptible to the Dark Light thing, but King Boo literally doesn't get phased.
He also directly created Spirit Balls, which are indeed little ghosts that have their own sentience, and his gem, upon dissipating, mellows the ghosts that were in the hotel, greatly implying he was the source of their hostility and mischief and that they're normally friendly. He doesn't need the Dark Moon anymore.
Also of note is the three magicians who can manipulate the floor your on to become a jumbled up mesh of a maze as well as take you into some pocket reality or something much like the LM1 Boss Ghosts. Certain rooms with a portion of the map (filled with mountains, stars, and even the Moon, can all be found in differing locations that they previously were. Likely just some minor spatial manipulation but still worth noting.
Lme is also impressive in a basic look at direct feats since Luigi can lift and slam a huge grand piano, tear off thick steel doors and even smash then to pieces, and can fend of ghosts capable of manipulating large pirate ships. There's also Gooigi, his Poltergust being able to disarm people and dispel thing backwards should he feel pressured or surrounded, his light being something NPCs (just E.Gadd), bosses, and normal enemies can react to. The size of things he can suck up and the sheer quantities and strategies he employs are also particularly noteworthy at leaat for DB so they can not downplay him should he return. Also some attack reflection via the Gust as well as the blast of air being able to knock projectiles back, particularly useful against the DJ boss when she throws her records.
