With Theros just having been released, and the second step of the Hero's Path events having happened over the weekend, the next thing on the agenda is Game Day, the culmination of the first part of the Hero's Path with Face the Hydra. This event allows players to finally use their hero cards - two of them at a time - and go on a one-to-four-versus-autopilot-deck adventure in an attempt to deplete the relentless heads of a Hydra-themed "challenge deck" that plays like Horde Magic.
MTGSalvation.com Rumor Mill moderator viperesque has early details on how the challenge will work. If you want the extra difficulty of not knowing what to expect and having to make up a strategy on the fly, you can stop reading here. Otherwise, check out this insanely detailed account of the Hydra:
The hydra challenge deck is a 60-cards. There are 19 head cards and 41 Sorcery cards. Up to four of the 19 heads start on the battlefield based on difficulty. The deck contains only 15 unique cards.
11x Hydra Head
4x Ravenous Brute Head
1x Snapping Fang Head
1x Shrieking Titan Head
1x Savage Vigor Head
(I am missing 1 in this count, but I'm fairly certain that there are exactly 19 head cards and that the count discrepancy is a missing Hydra Head or Ravenous Brute Head.)
When it dies, each player gains 2 life.
*Two, three, or four of these start on the battlefield at the beginning of the game.
Ravenous Brute Head
When it dies, each player gains 2 life and draws a card.
Snapping Fang Head
Deals 1 (additional) damage to each player during the hydra's end step.
(Has some sort of beneficial effect when it dies.)
Shrieking Titan Head
Each player discards a card during the hydra's end step.
(Has some sort of beneficial effect when it dies.)
Savage Vigor Head
The hydra draws/casts an additional card during its end steps.
The 41 unique spells are as follows
2x Strike the Weak Spot
Destroy target head. (You make all choices for the hydra.) If the head is Elite, the hydra takes another turn after this one.
4x Hydra's Impenetrable Hide
Heads are indestructible until the hydra's next turn.
3x Neck Tangle
Something about tapping two heads and then something else. (Tapped heads won't damage players during the hydra's end step.)
4x Torn Between Heads
I don't remember this one's text. (Note: This is probably creature removal or damage that depends on there being multiple heads on the battlefield.)
4x Grown from the Stump
Return up to 2 of the 0/3 heads from the hydra's graveyard to play. If there aren't any, reveal the library until you hit a head and put that into play and the rest into the graveyard.
5x Swallow the Hero Whole
I think this one was already spoiled, but it's like Journey to Nowhere. Each player chooses a creature they control to exile but those creatures come back when a head dies.
4 Hydra's Noxious Breath
Choose one -- 5 damage to each player or destroy each tapped non-head creature. (You make decisions for the hydra. We assume this means you can choose the latter option on turn 1 when you have no creatures.)
6x Unified Lunge
The hydra deals X damage to each player where X is the number of heads it controls.
5x Disorienting Glower
Each player can't cast spells until the Hydra's next turn.
5x Distract the Hydra
I don't remember the text of this one.There was a Sorcery to the effect of:
"Each player may sacrifice a creature. Each player that does so may tap a head. Each player that doesn't sacrifice a creature loses 3 life." (Tapped heads don't do damage to players during the hydra's end step.)
There was a Sorcery to the effect of:
"If the hydra has 5 or more heads, do something. Otherwise the hydra casts the top card of its deck." (The hydra never had five heads when we drew it so I don't remember what the first clause did.
The player(s) always take the first turn (and don't draw on their first turn.
The hydra "casts" the top card of its library each turn (again a ~15:41 head:spell ratio). During its end step, each untapped head deals 1 damage to each player. Each Elite head deals an additional 1 damage to each player. (Snapping Fang Head's ability thus causes it to deal 3 total damage to each player by itself since it's also elite.)
Players attack the heads directly with creatures.
When a head dies, the hydra reveals the top two cards of his or her library. Any heads come into play; any sorceries go to the graveyard. (Hitting double spells is not unlikely.)
The player(s) win when no heads remain on the battlefield.
As far as I can remember, the graveyard never reshuffles, so the 19 head cards (and 4 copies of Grown from the Stump) are the actual kill limit. (Though this will vary randomly based on the exact order of spells in the deck.)
The assumption is that players will use their Game Day deck, which has to be Standard, against the Hydra, but it's designed to be playable against any deck at all. A few things of note: Since the Hydra isn't a player, there's no victory-by-milling possible here. All of the Hydra Heads seem to have Hero's Reward triggers when they die, though it's not clear whether they'll all be cards and lifegain. Finally, the techiest of tech cards against this deck seems to be... Mannichi, the Fevered Dream; even though the heads Mannichi's activated ability severs via 0-toughness state-based effects may quite well regrow twofold, it's easy to reactivate that ability and clear the board over and over again until all nineteen are gone.
For those planning on battling the Hydra: Good luck! Looks like you'll need it.