Excava, the Risen Past

If another effect causes one of the returned permanents to become a creature and sets its base power and toughness as it does so, that creature will have that power and toughness; it won't be 1/1. However, a Vehicle returned this way will remain a 1/1 if you crew it, and a Spacecraft returned this way will remain a 1/1 even if enough charge counters are placed on it for it to become a creature.