I saw last night that Grever turns i to a multicoloured beach ball once you first beat him. osma is a mlticoloured beach ball so i recon that osma is grever of ff8. As ff9 is a lookback at the other final fantasy's I thought why shouldent O=G. It dose look simaler just biggger and slightly more colours. You also find it in an Ediolon cave/hole/thingy and Grever is a GF/summon from ff8.

PS: Cant spell Grever its the thing Ultimicia summons in ff8's final battle sequence.