They have a new effect that allows your characters to move there for a price
Creating multiple copies of powerful Slivers like Virulent Sliver, who can give slivers multiple instances of poisonous, or even just Predatory Sliver or Battle Sliver, who give a flat power buff to other slivers, is going to be one of the strongest strategies in this deck
It gains hexproof until end of turn
Is it easy to handle or is it a hassle
It's somewhat notorious for being a lengthy fight that can take upwards of an hour or two to actually finish, though the game developers initially planned to have the fight take upwards of two weeks to complete
If the chosen creature is copying something else (for example, if the chosen creature is another Phantasmal Image), then Phantasmal Image enters as whatever the chosen creature copied