Possibly the most complex competitive combo deck to exist in modern, Ad Nauseam is a collection of odd cards that somehow work together to win the game out of nowhere. The name sake of the deck is the card Ad Nauseam. For 3 generic and 2 black mana you reveal the top card of your library and and put it into your hand, then you lose life equal to its converted mana cost and you may repeat this process as many times as you want. This allows you to draw your entire deck in one turn. Yes, you will lose a lot of life, but more about how to get around that later. With your entire deck drawn you want to discard 3 Simian Spirit Guides into exile to generate 3 red mana. Then you will use that mana to cast your only copy of Lightning Storm and maintain priority while it is on the stack to discard all of the land cards in your hand to put charge counters on it and deal massive damage to your opponent. Now, how do you prevent Ad Nauseam from costing you the game? Phyrexian Unlife, which you should have played the turn before going off with Ad Nauseam. Since losing life from effects like Ad Nauseam don’t count as damage, it wont add any infect counters for the cards that you pick up. Instead, your life total will go into the negative numbers.
Protecting the combo and you from your opponent is another obscure interaction between two cards: Pact of Negation and Angel’s Grace. Pact of Negation counters a spell but you have to pay 3 generic and 2 blue on your next upkeep, which is after you untap all of your lands; you probably won’t have enough mana to pay that off, and even if you do your turn will not be an effective one. Instead of trying to pay all that mana or lose the game, you can pay a single white mana for Angel’s Grace, which prevents you from losing the game on that turn. You could also use Force of Negation if you want more counter magic, just be sure to have enough blue cards to discard like Serum Visions or something else that would be useful no matter how you use it. Thassa’s Oracle is another possibility that can be discarded for Force of Negation, but can also win the game should you need it to. Also note that Angel’s Grace can be used if your aren’t able to get a Phyrexian Unlife when you are ready to go off with Ad Nauseam. It won’t save you from going into negative life, but you won’t be able to lose that game on that turn and one turn is all you need.
As you may have noticed, this deck can be a little intense on mana. To help, the deck runs Pentad Prism and Lotus Bloom. Due to Pentad Prism’s sunburst ability, it gets a charge counter for each color of mana spent to cast it, meaning that the max it can have on it is two charge counters which can then be removed for 2 mana. Lotus Bloom is essentially a Black Lotus that takes 3 turns before you can use it. You will want to have a Lotus Bloom out on turn 1 or a Pentad Prism on turn 2, because they will help pay for Ad Nauseam. You will want some card draw so I will suggest Sleight of Hand and Serum Visions, at least one if not both.
The shell of Ad Nauseam should look something like the following:
Ad Nauseam x4
Simian Spirit Guide x3-4
Lightning Storm x1-2
Phyrexian Unlife x3-4
Pact of Negation x3-4
Angel’s Grace x4
Lotus Bloom x4
Pentad Prism x4
Serum Visions x4
When it comes to lands, this deck doesn’t need to use fetch lands. Since you want lands in your hand to discard to Lightning Storm, using fetch lands will essentially make 2 lands unusable, since you have to sacrifice the fetch land itself and grab a second land from the deck. Lands that can produce multiple colors and come in untapped are ideal. Gemstone Mine and City of Brass are great. Even though they come in tapped, a few scry lands from Theros are acceptable since the scry is free. Shock lands and check lands are great. If you are unsure about which colors to use, most of the spells you need are blue and white. Ad Nauseam is the only black card, but since it wins the game you will want to make sure you can produce it when you need to which is why the two artifacts are so important. Although you have red cards, you don’t need to worry about lands that produce red mana because the Simian Spirit Guides will be able to provide it.
As I said with Death’s Shadow, Ad Nauseam is one of those milestone decks that when played successfully proves that the player has a certain degree of mastery in Magic: The Gathering. Let me know what deck you want to see next in the comments down below.