Exploiting cards with ridiculous abilities is one way to win a game and this one is truly ridiculous. Each card on it's own is nothing special. Everything is either way too expensive or has a big drawback, but this is basically cheating.
There's no secret that Fleet Swallower and Fraying Sanity are too good to be in the same rotation. Having Sanity out and simply attacking with a Swallower will literally Mill your opponent out no matter what happens. The only outs for your opponent are to kill the Swallower before you declare attackers, counter the triggered ability of the Swallower as it attacks, or destroy the Curse before you begin your end step. That's it. When it is declared an attacker your opponent will Mill half of their Library and then your opponent has to Mill that same number of cards at the beginning of your end step. Doesn't matter if the Swallower hit your opponent, got chumped, or even died to blockers. It's stupid.
What could be more broken than that? I mean, you can't play the Swallower until turn 7 and then can't attack until turn 8, right?
No. With these cards you can do this as early as turn 4.
This does require a few planets to align, but they have a pretty good chance of getting there. The first requirement is the hardest one, and that is to get a Fleet Swallower into your graveyard on turn 2. The three ways to do this are with Cathartic Reunion, Compelling Argument, and Strategic Planning. Reunion is guaranteed to do it if you started with a Fleet in your hand, and Planning would just have to reveal one out of the top 3 cards of your library. Choose any other card and bury the Fleet. Argument would have to find one in the top 5 cards. That's it. Then, turn 3 you have to play Fraying Sanity. Turn 4 cast Madcap Experiment and if you hit God-Pharaoh's Gift you've basically won as long as it wasn't too deep into your deck. If done on your first main phase, the Gift will activate when you declare combat. Return the discarded Fleet to the battlefield except it is a 4/4 black zombie fish with haste. Once you declare it as an attacker your opponent must mill half of their library and then (almost) no matter what happens you win before the end of your 4th turn when the Sanity triggers to mill the other half of their library.
Obviously things can go wrong. You can miss Gift within the next 20 cards and just die to the Experiment. That would be truly unfortunate. The safety net here is that there are a few extra artifacts that you could hit. Thankfully, for some reason, they printed another artifact that specifically tutors the Gift and puts it right onto the battlefield. That means if you hit this instead you can just activate it for two mana on your next turn and finish the combo anyway. With up to 7 out of the remaining 45 or so cards being artifacts you shouldn't just die to Experiment. You could also miss getting a Fleet into the Graveyard, so it's best to have one in your starting hand. The big caveat with Gate to the Afterlife is that you have to have 6 creatures in the graveyard to use it, but with so many ways to dump your hand or mill yourself that shouldn't be terribly difficult as the backup plan. I did add some Enigma Drakes to the main board when I realized you couldn't just do it whenever you wanted, but it's still a very effective enabler as soon as you can do it.
I'm trying out a lot of different things that might work in place of the Gate, and Primal Amulet seems like a good one. Haven't really done any testing with it yet but on paper it seems to check out.
I'm also playing around with Combustible Gearhulk as an option since it draws or mills while getting damage in and being a good sized body. It's a good payoff from Madcap and the overall higher cost of cards in the deck means the damage from it's ETB could be lethal or close to.
The remaining cards in the deck just help you piece together the above scenario as it is basically the only win condition in the whole deck. Bloodwater Entity is a great card that buys back a spell to keep digging if you can't find one of the pieces. It flies and has Prowess so it is somewhat possible to win in the air, but I wouldn't count on it. Evolving Wilds and Field of Ruin help thin the deck to increase your odds of hitting a Gift with Experiment. Fateful Showdown can dish some nice damage to the face while cycling your hand away to dig faster. Finally, Inventors' Fair can just go get yourself a Gift if all else fails.
That. Is. It.
The sideboard has Abrade for dealing with creatures or artifacts. Negate is protection against a counter spell and instant speed removal that might stop you before combat with the Fleet Swallower. Sweltering Suns is a sweeper if you are up against fast aggro and tokens that can get nice and wide nice and fast and possibly kill you before you mill them. Spell Pierce is a great early game counter and could make a huge difference if timed right. Perilous Voyage and River's Rebuke are awesome against cards like Cast Out and Ixalan's Binding that might otherwise cripple your combo. They also provide tempo if needed. Finally, Drake Haven takes advantage of discarding cards regularly and makes Cathartic Reunion potentially deadly by allowing you to create up to 2 2/2 flying tokens.
This deck goes all-in to the Fleet Swallower + Fraying Sanity
combo, but I think it is fast enough to shut down a lot of decks. It should prove especially good against mid-range decks, but might have some issues against a counter heavy strategy that can stop you from getting your combo. You definitely can't afford to hard cast this stuff. It's cheap and unfair if you hit the turn 4 insta-win, but at least you get it over with quickly.
