With the recently-revealed Grumble card, Shaman can now deal infinite damage in one turn. Requiring just 6 cards, 3 turns, and an inhuman amount of APM (but notably, no dependency on stuff living through the turn, and no RNG), this extremely simple and feasible combo is likely to dominate the meta.

Turn 1 (Setup for Grumble):

1. Play two Fire Plume Harbingers while Grumble is in your hand.

2. Play Spirit Echo, to eventually return those Harbingers to your hand. This costs (6) mana and leaves you with a 4-Cost Grumble in hand.

3. (Optional) Since people have brought up that your harbingers could be silenced or transformed, despite how unlikely that is, you can also add a 7th card to the combo to guarantee you immediately get your Harbinger back, which would be by playing Wild Pyromanceer before your harbingers so they instantly come back to your hand. This only brings up this turn's total Cost to 8, so it's still possible.

Turn 2 (Acquire 2 Grumbles):

1. Once your Fire Plume Harbingers have returned to your hand, play one of them. This leaves you with a 1-Cost Harbinger and a 3-Cost grumble, and 8 mana left.

2. Play Grumble for (3) mana. This gives you a second 1-Cost Harbinger in hand, leaving you with 5 mana left.

3. Play Zola on Grumble to get a copy of it, leaving you with 2 mana left.

4. Play Brewmaster on that same Grumble to get it back into your hand. This leaves you with Two 1-Cost Harbingers, Two 6-Cost Grumbles, 0 mana left, and a 2/2 and 3/2 on board for some superb tempo.

Turn 3 (Go infinite):

1. Play both of your 1-Cost fire plume Harbingers, costing only (1) mana since the first one reduces the second. You now have two 4-Cost grumbles, and 9 mana left.

2. Play a 4-Cost Grumble, to get two new 1-Cost Harbingers in your hand. This leaves you with 5 mana left.

3. Play your second 4-Cost Grumble, returning a 1-Cost Grumble and two 1-Cost Harbingers to your hand. This leaves you with 1 mana left.

4. Play a 1-Cost Harbinger. This leaves you with 0 mana, but a Grumble and Harbinger in play, as well as a 0-Cost Grumble and 0-Cost Harbinger in your hand.

5. Once you've reached this point, you can now play Grumble to get a 1-Cost Grumble and 1-Cost Fire Plume Harbinger, then play a Harbinger to reduce those both to (0). This cycles infinitely.

6. Depending on how long your damage-dealing elemental (Fire Plume Phoenix, Fire Elemental, Blaze Caller, Al'Akir) has been in your hand, it will Cost some small amount of mana. Keep doing the Cycle until it costs (0), then add it into the cycle - playing it between each set of Grumble and Harbingers. Grumble returns it to your hand costing (1), and Harbinger makes it cost (0), so you can play it for free along with the cycle.

7. Now, you have to scramble to play your damage-dealing elemental as many times as you can, hopefully getting enough damage in before the turn timer expires. This leaves you with infinite damage, and carpel tunnel.