You can think of this kind of like the difference between a set of polygons and the bumpmap that goes on top of it, if you're familiar with 3D animation at all
So far, only five games have been revealed for the collection: Yu-Gi-Oh Duel Monsters (1998, Game Boy) Yu-Gi-Oh Duel Monsters 2: Dark Duel Stories (1999, Game Boy Color) Yu-Gi-Oh Dark Duel Stories (2000, Game Boy Color) Yu-Gi-Oh Duel Monsters 4: Battle of Great Duelists (2000, Game Boy Color) Yu-Gi-Oh Duel Monsters 6: Expert 2 (2001, Game Boy Advance) Even though its a short list, its an exciting one
Unlike several of the other Mega Evolutions on this list, Mega Gengar ex only focuses on the Mega Evolution itself, and doesn't include the evolution line
9, with the "Roll for Initiative" Secret Lair Superdrop delivering various reprints of spells and characters all set in the Forgotten Realms