|Advanced Crystal Beast|
The seven "Advanced Crystal Beasts" and "Rainbow Dark Dragon" in the artwork of "Advanced Dark"
"Crystal Beast"-orientated Spell and Trap Cards also work on "Advanced Crystal Beasts" on the field, since their names are treated as the same as their normal "Crystal Beast" counterparts. But, they have a weakness: they can only be face-up on the field with the Field Spell Card "Advanced Dark" in play, otherwise they are destroyed. "Rainbow Dark Dragon", in the anime, can't exist without all of the "Advanced Crystal Beasts" on the field, or in the Graveyard, otherwise it will be banished.
The "Advanced Crystal Beasts" have not been released in TCG or OCG, though "Rainbow Dark Dragon" (albeit with modified Summoning conditions) and "Advanced Dark" have been released in Duelist Edition Volume 2 and Phantom Darkness in the OCG and Phantom Darkness and Return of the Duelist in the TCG. "Advanced Dark" has appeared in some of the Tag Force games with altered effect(s).