I think every leyline probably merits attention. If you can force your opponent to play a fair match this could do gobs of damage. Probably not a contender in vintage but who knows.

Patently nuts in modern and maybe legacy.

Cute vs storm triggers.

Cute versus ballista blowouts.

I really like the card, and I can see it as troublesome for multiple archetypes. But in the end, I think that it is too situational for it to see any regular play.

@cambriel

How would this stack against Tendrils? Do they die or just heal back all the damage it deals?

@vaughnbros All the copies go on the stack at the same time, at which time they choose a target and this triggers, and resolves as LIFO. After this, each copy resolves one at a time.

I'm however a bit rusty and I'm not sure if the trigger from Leyline for the original spell would resolve before Storm triggers or not, probably depends on whose turn it is.

So, in order:

1. Player casts Tendrils
2. Leyline triggers and Storm triggers
3. Leyline for original Tendril resolves
4. Storm resolves
5. Copies are placed on the stack and choose a target
6. Leyline triggers for each copy
7. Leyline resolves for each copy
8. Each copy of Tendrils resolves
9. Tendrils resolves

Do note that if the Storm player has more life than the player with Leyline, they can target themselves with some of the Tendrils copies to stay at the same life total without triggering Leyline.

@wagner said in [M20] Leyline of Combustion:

I'm however a bit rusty and I'm not sure if the trigger from Leyline for the original spell would resolve before Storm triggers or not,

If multiple triggers from the same controller would go on the stack at the same time, the controller chooses the order. Since these (storm and leyline triggers) are most likely not the same controller, then triggers from the active player go on the stack first, then triggers from opponents go on the stack.
So with this in play if somebody casts tendrils the stack would look like this

1. Leyline trigger to deal 2 damage
2. storm trigger
3. tendrils spell

Leyline triggers and deals 2 damage to the storm player.
Storm trigger goes off, say 3 copies. A target is chosen for each copy and goes on the stack, each of which triggers leyline.
The stack is now:

1. leyline deals 2
2. leyline deals 2
3. leyline deals 2
4. tendrils copy
5. tendrils copy
6. tendrils copy
7. tendrils
   (all assuming the tendrils player just targets everything at the person with this leyline in play).