The only way I can think to really make this work, a card with a selectable choice of cost and damage, would be to have a no-cost quick card that summons the selected choice. Mode 1 draws a 1/1/1 Attack=4, Mode 2 draws a 2/2/2 Attack=8, etc. Adding a card classification such that it cannot be chosen for a deck but only drawn by card effect has been discussed before.
As already discussed, simple stock reduction doesn't work because you could (and, in effect, are encouraged to) play it when you have less stock than the effect would alter. Having it halt production doesn't change this, and it still leaves the opponent without a way to prevent or dissuade its play.