Lumbering Laundry

Once it has resolved, Lumbering Laundry's first ability lets you look at face-down creatures whenever you want until end of turn, even if you don't have priority. This action doesn't use the stack. Knowing what those cards are becomes part of the information you have access to, just like you can look at the cards in your hand. Once the turn ends, however, you can no longer look at those creatures.

The face-down spell has no mana cost and a mana value of 0. When you cast a face-down spell, put it on the stack face down so no other player knows what it is, and pay 3 generic mana to cast it. This is an alternative cost.

Lumbering Laundry's first ability doesn't let you look at face-down spells you don't control on the stack.