The Galactic Nova Nucleus (originally called the Heart of Nova) is the core of Nova. This boss appears in the game Kirby Super Star and its remake. It contains clusters of mechanical spheres that move up and down on electric bars surrounding Nova's actual heart. Damage can be avoided simply by dodging the spheres. Kirby simply has to shoot down the small energy spheres with the stars shot by Starship to damage Nova. However, Kirby has to be careful, as the towers can crush him against the sides of the screen. There are eight columns total, and Kirby can destroy the columns in any order he wishes, but there may be some prices to pay if he isn't careful.
When two of the eight columns are destroyed, the columns start moving a bit faster than before. Upon having half the total amount of columns destroyed, they start moving at rapid speed. When Kirby destroys a fifth one, Nova will make the columns orbit the heart in the opposite direction. When there is only one working column left, Nova's heart begins to spin rapidly. The quickest way to defeat this boss is to destroy the first four columns, partially damage the fifth and sixth column, then destroy the seventh and eighth column before returning backwards to destroy the remaining columns.
When all of the columns are destroyed, every moving object stops as the place starts to self-destruct. Kirby soon escapes just as Nova blows up. Part of his head explodes and one of his eyes closes. Right after he escapes the now-malfunctioning machine, Kirby will have to fight Marx.
- The fight with Nova's core (as well as the entire level leading up to it) seems to reference a well-known and humorous tradition in the famous Shoot'em up series, Gradius. The final boss does not put up much of a fight and is dispatched rather easily, this being the reason why the level preceding it is deemed harder than the actual fight. In this case, all Nova can do to fight back is to try to hit Kirby with the energy columns rotating around his heart although this does prove to be fatal if not avoided.
- In Kirby's Return to Dream Land, the level Another Dimension is traversed in a similar fashion to Nova.
- Nova is also referenced by Magolor in the same game.
- Nova's actual heart spins clockwise in Kirby Super Star, but counterclockwise in Kirby Super Star Ultra.
- The fourth phase of Star Dream Soul OS is a reference to this, with the battle containing pillars rotating around a heart and the summoning of enemies much alike the ones summoned by Nova. The battle takes place on foot instead of in the Starship, although the UFO ability can be used, making the battle more similar to the original.