Gaspar is a nightcap-wearing, limbless ghost with a long, ghostly tail. Because it has appeared so few times and its debut game was in monochrome, there is some inconsistency to Gaspar's coloring. In official artwork for Kirby's Dream Land, it is pale white with red cheek blushes and a red nightcap. In Kirby's Dream Course, however, Gaspar is a creamy shade of yellow, and its nightcap is dark blue with a neon green trim.
Gaspar serves as the equivalent of Booler in the Extra Game of Kirby's Dream Land. Gaspar lives in Castle Lololo, where he floats around like Booler, but at a higher speed and usually in a set pattern. It is stronger than its counterpart, dealing two points of damage when it collides with Kirby. The enemy has the tendency to wiggle its tail as it floats around.
Gaspar is one of the few enemies that is required to be hit with a high-angled shot in order to be defeated.
Gaspar's name may be a reference to the animated character Casper the Friendly Ghost, based on the similar appearance. Alternatively, Gaspar's name may refer to the fact that, prior to the release of Kirby's Dream Land, "Gaspar" or "Gasper" was one of the alternate names that Nintendo of America suggested to HAL in place of "Twinkle Popo," the name that HAL originally proposed for the character that became Kirby. The name could also be derived from gasp, an inhale performed in response to shock.