Animate Graveyard

Similarly, if Animate Graveyard leaves the battlefield or becomes unattached from your graveyard, the animated graveyard will return to being just your graveyard.

While you'll use the cards in your graveyard to determine the stats and abilities of your graveyard-that's-a-creature, those cards aren't themselves on the battlefield. For example, if you mill a card while your graveyard is animated, the milled card doesn't enter the battlefield. This isn't quite as wild as Yet Another Aether Vortex.

Once enchanted, your graveyard behaves like any other creature. It can attack or block. You can enchant it with other Auras, equip it, use it to crew Vehicles, and so on. It won't naturally have any creature types—the text box doesn't include the type line.