Taking a look, the arm shooting out to the right and the pose looks like a previous Ravensburger card used in the Villainous game
the copy ceases to exist the next time state-based actions are performed
To determine the total cost of a spell, start with the mana cost or alternative cost you're paying (such as a flashback cost), add any cost increases (such as kicker costs), then apply any cost reductions (such as that of The Water Crystal's first ability)
Remember, even without a Detective, Plutos ability still puts the Item on the top of the deck if not your hand
The simple counter to this is your opponent not challenging
There's also some weak cards like Interceptor, Shadow's Hound which is really cool and self-reanimate is thematic, but there's only a single Assassin in the deck (not even a commander) and a 4/3 without evasion is simply not worth getting back anyway