As the name suggests, this thread is all about the worst cards in the game! From the ones that are simply hard to use to the ones that just plain suck, this is where those cards are embraced instead of ignored. First off, no base set Ghastly, I'm pretty sure we're all familiar with how terrible that one was.

Anyways, my worst card (out of the ones I own) would have to be Black Kyurem (Boundaries Crossed 100/149).
This is a legendary, so it must have high hp and awesome moves, right? It does have fairly decent hp (130), I'll give it that much, but its attacks make it one of the most difficult Pokemon to use effectively. To prove my point, here are its moves:

Dual Claw
Power: 20x
cost: Lightning x1, Any type x1
Description: Flip 2 coins. This attack does 20 damage times the number of heads.

With this move, you have an eleven foot tall dragon (10' 10" if you want to be specific) doing a whole 20 damage every turn, 40 if you're lucky, and there's always the possibility of this move doing nothing at all! I honestly want to know just what was going through Nintendo's minds when they came up with this move. At least its other attack is actually useful:

Flash Freeze
cost: Water x1, Lightning x1, Any type x2
Power: 100
Description: Discard an energy attached to this Pokemon.

This is actually a pretty good move. It's just that the high cost and the discard that's required every time you use it will allow Black Kyurem to eat away all of your energy resources if you aren't careful. Well, that's my worst card!
I'd like to see what all of you have to say about this topic, so feel free to post your own. Just remember this:
There is no one worst card, a card's value and effectiveness depends on your play style.