Damn, I love what Wizards has done with introducing what was probably supposed to be a meme card into the card pool. The sad thing is that Fblthp is actually REALLY good with Proteus Staff. I'll explain the interaction after I post the decklist, but you can essentially find any 2 card combo you want. Reddit has already gone wild with formulating piles and card sequences, and I unashamedly repost those ideas here. Do note that I have never liked Lion's Eye Diamond and will not be including it within my list, even though it's part of some powerful lines.
Anyways, this is my take on Fblthp if I were to build him.
Besides winning with a meme creature? It's a control strategy. But to help you understand better, this deck aims to use Protues Staff to maximum effect.
Because of Fblthp's unique ability to draw you 2 cards if he is put into play from your library, you have the ability to draw 2 cards with Proteus Staffafter rearranging your WHOLE library in the order you choose. This is massively powerful. The actual mechanics of the combo are that you target Fblthp with the Staff's ability and put Fblthp on the bottom of your library. Since it's the only creature card in your deck, it will come back into play from your library, drawing you 2 cards. As part of resolving the Staff's ability, you also get to order the cards in your library in whatever way suits you best.
This means that you can essentially put whatever 2 card combo you want at the top of your library and you will draw it via Fblthp's draw trigger. The ideal 2 card combo to immediately draw, depending on your board state, is DramaticScepter. If you have enough mana sources in play, you can immediately create infinite mana. But what's neat is that you can ALSO draw your deck, since the Proteus Staff can repeat the "combo" with Fblthp to draw 2 cards repeatedly, allowing you to find whatever win condition you want. I like having 2 just in case something goes awry or someone Praetor's Grasp you.
But, what's really cool about this unique combo, is that you can also win immediately upon resolving the Staff's ability. The sequence of cards would be as follows, and requires that 1 player have at least 5 cards in hand:
Any mana floating/available shortcuts the number of cards that you would need to pile on top of your deck. Fblthp's draw trigger will draw the first two cards of the above pile. You would then cast Gush for its alternate cost to draw the Amber and Windfall. Use the Crypt and the Amber to cast Windfall. With a 5 card hand present at the table, you then cast Windfall and draw the remaining cards needed in order to combo off. You cast the Opal for free and tap it for mana to cast Mana Vault. Tap Mana Vault to cast AND activate Voltaic Key, untapping the Vault with 1 floating. Tap the Vault again, for a total of 4 to cast Scepter and activate it with Dramatic Reversal imprinted on it.
Another pile that you can use regardless of hand size but requires at least 3 lands and an open land drop or 4 lands in play is the following:
Fblthp's trigger will draw you Gush and the Crypt. Cast Gush for its alternate cost to draw Frantic Search and Mox Amber (Fblthp will be in play after resolution of Proteus Staff). Use the Crypt and Amber to cast Frantic Search, untapping 3 lands and drawing Brainstorm and Mana Vault, discarding 2 cards. With 2 land untapped, cast Brainstorm to draw into Voltaic Key and Dramatic Scepter. Tap one of the lands to cast Mana Vault. Tap Vault to cast AND activate Voltaic Key, untapping the Vault with 1 floating. Tap the Vault for a total of 4 floating. This is enough mana to cast Isochron Scepter and activate its ability, untapping all artifacts and allowing you to ccombo off.
Same basic principle to open up the pile. After drawing Gush and Mox Amber, you then cast Gush for its alternate casting cost. Cast Brainstorm with Mox Amber. Draw Mana Vault and Dramatic Scepter, put 2 cards back. Cast Mana Crypt. Tap Crypt to cast Mana Vault, 1 floating. Tap Vault to add 3, for a total of 4. Cast Scepter and activate it with the floating 4 mana and proceed to win.
The primary win condition in the deck is Blue Sun's Zenith to deck your opponents. The backup win condition is Aetherflux Reservoir because the idea of Fblthp arming the Doom Laser of Destiny is absolutely hilarious. The best one is to spend 63 turns of keeping your opponents' board clear via Capsize and killing them via Commander damage, 1 poke at a time (shuffling in Blue Sun's Zenith to keep yourself alive). Who knew that Fblthp would be such an awesome Assassin General?
The cards I preordered for this list came in, so I'm actually going to give it an honest test.
I'm also half-inclined to make this Counterspell.dec since it's really only looking to find a window to execute its combo and wants to control the game until that point. I'll edit the OP once I've settled on a final configuration.
I'm seriously thinking about homogenizing the 3 separate mono-Blue cEDH lists I have into a cohesive mono-Blue Core list, with the separate pieces of my Teferi, Memnarch, and Fblthp lists being an interchangeable set of cards that's included in the deck-box. This would allow me to play whatever cEDH mono-Blue list I'm feeling like playing without having to drag out my binder and make the changes every single time.
I've often thought about analyzing my mono-U cEDH lists and determining what specific cards constitute the core of the deck. The idea behind this is if I can generate a cEDH mono-U template, then I can take all of the cards for the 4 different Commanders I play and put them in one deck box for deckspace efficiency and card collection efficiency as well. So, after some time analyzing the decklists I have, the below list is the Mono-U cEDH "Core", as I see it. Do note that this list is NOT comprehensive, since it was done based on my own limited research, but I feel confident in saying that this core list will give any player a fantastic starting base whenever they decide to build a Mono-U cEDH decklist.
This is the core 95 cards that are represented in 75% of the cEDH Mono-U decks that I’m currently playing and which are represented in a significant number of TappedOut lists that I can find for cEDH Mono-U lists. This leaves 4 slots to customize for each of the respective Commanders that I run, namely Urza, Lord High Artificer; Memnarch; Fblthp, the Lost; and Teferi, Temporal Archmage.
So, this means that I have 4 slots I can dedicate to each respective Commander without technically altering ANY of the other 95 cards. This will allow me to carry one deck box for any of the 4 Mono-Blue decks that I have Primers/decklists for on MTGSal, allowing me deck portability and card collection compactness. But, for completeness’ sake, I’ll list the actual changes I would make to each deck so that each list runs optimally.
I've played this deck a few times against my wife's Kaalia deck and it has done VERY well. Even if Proteus Staff gets exiled, it still has a backup win condition line that doesn't interfere with the primary combo line. I'm curious as to how he'll test out in a true cEDH Multi-Player game, but my initial tests show that Fblthp is actually a decent deck.
I still relish the flavor of Fblthp accidentally stumbling into the mechanism chamber that causes Aetherflux Reservoir to fire off. Like, Fblthp is so lost that he ends up in a room with a big red button. He keeps clicking the button, expecting a certain door to open, but little does he know that he's actually murdering other Planeswalkers with a giant Death Laser. Poor Fblthp! He never intended to be a murder master!