Talk:Pokémon VS Digimon/@comment-2255534-20160107232957/@comment-1652808-20160108000507

"Later, Dr. MacLain's attempts to duplicate the shield, minus Wakandan Vibranium and the mystery factor, resulted in true Adamantium. Because of this historical link, the unknown substance composing the shield is sometimes referred to as "proto-adamantium"."

The original shield is made out of Vibranium. the Proto-Adamantium version is an alternate and Cap never uses it.