If you cast a spell "without paying its mana cost", you can't choose to cast it for any alternative costs
On a normal day, you might think that giving your opponent a creature is not exactly a good upside, but when Toxrill is out, you will get some slugs because Toxrill will kill these 1/1 Spirits at every end step (if you have tapped Forbidden Orchard for mana, that is)
If you do, put this card into your hand as it resolves.) Evincars Justice deals 2 damage to each creature and each player
For example, if you already have a Curse-based deck with Lynde, Cheerful Tormentor, both are welcome cards
However, the plane of Duskmourn is an endless haunted house, and the artwork and cards suggest that a group of survivors has entered it and must find a way to escape the horrors haunting the halls