Would we rather do damage based on power, or perhaps on converted mana cost?

Converted mana cost might make this better to hose down re-animator strategies, and if you're playing against a deck that runs efficient enough creatures for power to be a better option, playing this card is probably not a good idea (first you have to kill an efficient critter, then play this card that doesn't effect the board)

I didn't even think about Null Rod.  What if we re-word it's second ability to be a triggered ability instead, so that it doesn't get shut down by Null Rod?

Mana Prison
4
Artifact
All Lands tap for Colourless mana instead of their regular colours.
Whenever a player would play a mana ability, he or she may pay .  If they do, they add one mana of any colour to their mana pool.

Take em' outside
U
Sorcery
You and target oppoent both skip your next turns.
Draw a card.

I like the idea of making cards with multiplayer games in mind, however this might be a little too useless in 1on1 play.  That's why I tacked the draw a card onto it, so that it wasn't a total waste.

Current Version:
Time Out

Sorcery
Target opponent skips his or her next turn. That player chooses an opponent. That player skips his or her next turn
Draw a card.

Meh, it's a little boring.  It's just burn.  It's not interesting at all.


Either he should not be an elf, or his ability should be to only give himself +1/+1.  Elves have a habit of generating lots of mana, and this guy gives them a way to spend it to do some evil things.


It's card advantage, and a counterspell in one.  It's everything a blue mage would ever want, but should never have.  It's just too strong.


Two Words: Howling Mine.  'nuff said.

Mana Prison
4
Artifact
All lands tap for colourless mana instead of their regular colours.
2:  Add one mana of any colour to your mana pool.  Any player may play this ability.

With Burning-Tree Shaman available now, this might be a little too strong.

How about this instead:

G
Sorcery
When you play ~ reveal a green creature card with converted mana cost 3 or less from your hand.
If ~ is countered discard the revealed card.
An opponent may discard two cards that share at least one colour to counter ~.
Put the revealed creature into play.

So now, it's closer to dark ritual, in that you do lose something else as well if it gets countered, and it allows your opponent to force of will it, if you try to do something too broken.