It's a neat idea. I'd just like to hear why you think that this belongs to Green. You mentioned that it's anti-Morphling and anti-regeneration and those can be construed as blue and black aspects, the enemies of green. On the other hand, this shuts down a lot more than those! Also, it should probably read "Activated abilities of creatures and artifacts without
in their costs cost an additional
to play." That way you avoid conflict with the old rule that enchantments don't tap. Also, don't forget a current wording post, in bold, without the graphical
symbols.
