"Carbon" is used here as a description. It means something that is absolutely 100% exact of another. Not similar, not related, not sort of like, neat a cheap copy but absolutely the same. Down to the carbon molecules. A carbon copy if you will.
"Henna, do you remember that key you gave me the other day to access the locked cabinet in Mr. Senner's office ?"
"Yeah, I do."
"Opening it I found a copy of the key sitting on the bottom. Carbon."
"That's strange. There's only supposed to be one. What good does it do in there ?"
the best Halo 2 team in the world consisting of Shockwave, Gho57ayame, Gandhi,and Karma (ffa king) whom has more than the skill to win every mlg tourny and is only rivaled by the worse team Final Boss