Mutable Explorer (Lorwyn Eclipsed Promos #186p)

Creature — Shapeshifter - {2}{G}
Changeling (This card is every creature type.)
When this creature enters, create a tapped Mutavault token. (It's a land with "{T}: Add {C}" and "{1}: This token becomes a 2/2 creature with all creature types until end of turn. It's still a land.")
1/1