Cameo (ConceptTopic, 2)
From Compile Worlds
A cameo occurs when someone (or, used more casually, something) appears, usually unexpectedly, but causes very little actual effect to their surroundings. Cameos are often inserted into created works as easter eggs or for some other entertaining purpose. Sometimes, though, they occur because a character was intended to be in the roster for a certain video game, but got cut due to practical issues that cropped up later in development. This may well have been the case with Harpy in Puyo Puyo 7.