Lately I've been playing around with making a deck centered around Rage Extractor, and I've noticed that every creature with Phyrexian mana in it's mana cost is an artifact creature.. So, can I drop a Cavern of Souls on the field and name "Artifact" as the creature type?
It makes sense to me, but I want to be for certain..
No because artifact is not a creature type but a card type. The only things you can name are to the right of the "-" like Myr in the example of "Artifact Creature - Myr".
"Artifact" and "Creature" are both card types. Subtypes appear after the hyphen, and "creature type" means a subtype of the type "creature".