Conspiracy | Magic: The Gathering
Formats Conspiracy is Legal in
Official Oracle Text for Conspiracy
Creature cards you own that aren't on the battlefield, creature spells you control, and creatures you control are the chosen type.
Official Rulings for Conspiracy
10/4/2004 : This can grant a creature type to animated lands and artifacts that would otherwise have no creature type.
8/1/2005 : "Legend" is no longer a creature type, and may not be chosen.
8/1/2005 : If you choose Wall, then your creatures can still attack because creature types don't confer abilities such as defender (any more than, say, choosing creature type Bird would confer flying).
9/20/2013 : Affected spells, cards, and creatures lose all of their other creature types.