Overgrowth Mechanic 3: Spurn

And now, things get complicated. Behold the spurn mechanic.

Spurn

Spurn is an ability that will appear solely on instants or permanents with flash. Spurn triggers when the spell is cast in response (on the stack) to an enemy's non-creature spell. In all cases spurn boosts what the spell does or adds additional effects. It's a reward for good timing when playing spells.

EDIT: Big templating error in the post and the card mock-up. Spurn only triggers off an opponent's non-creature spell. Important distinction. I've updated the blog post and the card mock-up.

Spurn will appear in green, blue, and white and represents how the civilized forces within these colors are trying to manage all the overgrowth. Even though green and white both see this abundance of life as a good thing (and refuse to recognize the disease effects) they nevertheless cannot ignore its potential for it getting out of control.

Spurn is inherently a defensive/punish kind of mechanic, so that's why it's in these colors, particularly blue and white. I'm not entirely sure if I'll keep it in green, given how prominent a role mutate will play in green, but there is a green/white faction within the set attempting to "manage" this growing mess, and spurn does fit in green.

Spurn's roots are messy and complicated and the wording of this ability still needs work. I believe the way I have it templated right now means that the spurn effect would still happen even if the spell itself is countered, which is not what I want. Spurn went through a series of names and iterations. Originally it was kind of like a mini "storm" effect, where the spell was more powerful for each other spell that was on the stack when it resolved. That proved to be absurdly complicated when the reality was in most cases it was probably going to trigger only once. So I decided to make it a simple either/or test.

Originally I had planned it for Grixis colors (blue, red, black) and it was called "retaliate," because of the trickery involved in casting it. But when I really started thinking about how the mechanic actually operated, it was about reacting and potentially punishing aggressive opponent behavior, and that felt more blue/white at the least. Also, I was really struggling with how to represents white's role in this set mechanically, and defensively attempting to keep things under control seems to fit well.

I expect experienced players will love this mechanic, but I worry it's too complicated to newer players. Do they understand it's referring to the stack? Do I need to reference the stack in the ability's text? Does that make it even more confusing if I did?