string key -- The name of the key to look up.
entity -- Entity found that has the name of the value matching the key given.
Looks up meta data from the object. In the case of entities, this will come from the associated entity def as well as any overridden values specified in worldEdit. The game will then look for an entity with the value of this data, and return it. If no entity with the given value is found, the returned value will be null.