The blue Ness represents the Ramblin' Evil Mushroom, a small mushroom enemy who appears as the item.
The stage represents the grass areas in EarthBound, which feature the Ramblin' Evil Mushroom as an enemy.
Other trivia:
This spirit's Support and Ramblin' Evil Mushroom equipped ability reference the Ramblin' Evil Mushroom's appearance as an item in the Super Smash Bros. series.
In World of Light, the Ramblin' Evil Mushroom spirit is located in the Forest Hill map, further referencing the grass areas in EarthBound, which feature the Ramblin' Evil Mushroom as an enemy.
