I can't help myself: Possession, how is this not an Attack? Especially coupled with Masquerade or Ambassador in your opponent's hand.
A card that needs an entire page in the rulebook can't possibly be good...
And Black Market, I'm glad this is a Promo card, we don't all have every expansion so the Black Market deck in live games may not always be really representable. I also don't like the luck factor.
With no trashers in the normal kingdom, you find a Witch in there and I find a Bureaucrat, gg.
Philosopher's Stone? Slows the game down way too much.
Ok, so much for the existing cards, notice how 2 are from Alchemy? The worst set, no surprise there.
Now some examples of awful imaginary cards. To be truly awful, a card has to do at least one and maybe more than one of these things:
- Increase variance/luck (and frustration levels)
- Be too dominant (a must buy regardless of setup)
- Be utterly useless
- Need a page long FAQ
- Be subtle, there's no fun making a card that instantly wins or loses the game for you
Vial of Poison
Cost: 2
Treasure - Duration
+ 5$
Once played, this card will not be cleaned up for the entire game.
Every following turn the $ value decreases by one.
Why? Because you will likely need this early in the game, because you don't have much money then, but when played in turn 3, by turn 10, its value is already -$2.
Medusa
Cost: 4
Action - Attack
+1 Action
Pick a player, this player loses his turn, but may set aside 3 cards from his hand and take them in hand the next turn.
Why? Donald hates targeting a singe player. Most attacks / actions target every player or the player to your left. Spam this every turn and your opponent will be paralyzed.
Leech
Cost: 5
Action - Attack
The player to your left reveals and discards the top two cards from his deck. Gain a card costing exactly the same as the other two cards together.
Why? Extremely luck dependent. Have your opponent turn over 2 Coppers and gain a Copper, have him turn over a Province and a Copper and gain a Province.
Have him turn over a Province and an Estate and gain nothing.