* Red-Eyes Black Metal Dragon's summoning requirements: It requires 2 "Red-Eyes" monsters as tributes.
* Rare Metalmorph's effect: It allows you to Tribute Summon a monster with the same name as a monster in your Graveyard.
The problem: Even if you have a "Red-Eyes" monster in your Graveyard, Rare Metalmorph doesn't let you Tribute Summon "Red-Eyes Black Metal Dragon" directly. It only allows you to Tribute Summon another monster with the same name as the one in your Graveyard.
To summon "Red-Eyes Black Metal Dragon," you would need to:
1. Have two "Red-Eyes" monsters on your field.
2. Tribute both of them.
Rare Metalmorph is useful for reviving monsters from the Graveyard, but it won't work for summoning "Red-Eyes Black Metal Dragon" due to its specific summoning conditions.