Creeping Cold is a 2nd level Druid spell with a duration of three rounds. It states that it does 1d6 "cumulative" damage, and goes on to explain that it deals 1d6 damage to its target the first round, 2d6 the second, and 3d6 the third.
So, if I cast Creeping Cold with Extend Spell, it seems as though it should last six rounds, dealing 1d6 damage on the first round, 2d6 damage on the second round, and so on up to the sixth round where it does 6d6 damage.
The problem with this theory is that Masters of the Wild contains another spell, Greater Creeping Cold, with a duration of 4 rounds. It's 7th level! So how, in your opinion, should Extend Spell and Creeping Cold interact?
So, if I cast Creeping Cold with Extend Spell, it seems as though it should last six rounds, dealing 1d6 damage on the first round, 2d6 damage on the second round, and so on up to the sixth round where it does 6d6 damage.
The problem with this theory is that Masters of the Wild contains another spell, Greater Creeping Cold, with a duration of 4 rounds. It's 7th level! So how, in your opinion, should Extend Spell and Creeping Cold interact?