For those of you who would like to understand without looking up rules:
MTG abilities work in a stack order. So as you play cards, activate abilities they "stack" up and then resolve down from the top.
Here, we start with replication, then creakwood, then doubling season, then lives, then vigor. So in essence you achieve the following by essentially going backwards:
1) Double your tokens made, and the counter placed on things (x2 tokens x2 counters)
2) double your tokens (x4 tokens x2 counters)
3) double your tokens and counters again (x8 tokens x4 counters)
4) copy another nonland permanent an make a token of it (target creakwood to now have 2 creakwoods)
5) creakwood X2 now create (16) 1/1 worms, that become (16) 3/3 worms.
6) each turn you repeat, increasing the number of worms you are generating, as well as their attack and health. OR occasionally target on of the enchantments (which are permanent non-land cards) to further increase how many worms you have.
Ideally imo, id target creakwood at least once because extra attack and health for worms, but also because its initially 2 activations of summoning worms which, with the base X8 worms, will easily overwhelm your opponent. Targeting an enchantment after simply raises your worms numbers exponentially from there. (X16, x32, x64) and that's assuming you don't kill them outright. Unless they have flying creatures, you can block (almost) anything they throw at you, and the swarm will be so large that they will likely never have enough ways to block your worms from devouring the measly 20 life points they have :^3
I have a somewhat similar combo involving a hydra (comes i to play with X 1/1 counters for each mana spent to play it, pay i think 4 to double it's counters), a card that makes two cards deal damage to eachother, and honest nest (creates a 1/1 flying death touch ((instakill to creatures)) for each point of damage it takes) hehehee..... people did not like my angry buzzing friends~
@asteroidtroglodyte i feel like you'd appreciate this post to
