Godrot Control

-MAIN DECK 40-
3|Rope|Lunarslayer Godrotter Raymarrow
3|Dsa|Dark Enchinoderm
3|Rope|Kotei Umiryu
3|Rope|Tekkairyu
2|Rope|Mordant Cetugon
2|Clpc|Nox Exploiter
1|Rope|Vanilla Knight

3|Nasb|Sudden Evaporation
3|Dodm|Lifeforce Shield
2|Dead|Below the Thunders of the Upper Deep
2|Dodm|Pirate's Grotto
2|Dirb|Scrap Destruction

3|Anv2|Declaration of Supremacy
3|Anv1|Hostile Negotiation
2|Rope|Death from Below
2|Dsa|Effect Disorientation
1|Clpc|Gift from Diabolus

-EXTRA DECK-
2|Qrev|Peeping Eye
2|Qrev|Tomocyrba
1|Qrev|Deity of Reoccurrence, Ouroboros
1|Qrev|Storm Valkyrie, Morrigan
1|Rope|Lifeless King of Death Anchor
2|Anv2|Ascendant Leviathan
2|Ww3|Axe-Arm Mantis
1|Dsa|Shark Bomber Mk3
1|Dodm|Spectral Hierophant
1|Dsa|Speartongue Serpent
1|Dsa|Neoflame Knight

-SIDE DECK-
2|Acrd|Hellcrescent Strix
2|Dirb|Black Raven of the Grave
1|Acrd|Icevale Witch
2|Anv2|Wretched Abyss
2|Dsa|The Trumpets of Armageddon
2|Rope|Ultimatum of Maria
1|Flfs|Stabilization Dome
1|Ww3|A Solemn World
2|Dirb|Blizzard

So, Vanilla Sea Serpents have always been a pretty fun deck, but not exactly threatening. In a game where being able to control the game and grind out wins decides matches, just being able to summon a big Vanilla didn't really matter when it was simple for fast rogue decks to summon something more threatening, or for the top-tier Decks to slow you down to the point that their 1-for-1's to strip away your options.

Now though, the Deck has access to something no other deck can make use of - Declaration of Supremacy. Simultaneously shutting down mass Special Summon decks like Chaos, Antennae and Mezzo and the advantage grind of Pteryx and Nox, this deck now has the ability to put itself in a game winning position as early as turn 1. A starting turn ending with Godrotter, Supremacy and Lifeforce/Hostile is damn near unbreakable and the pressure you can put your opponent under with a 3000 beater can end games fast.

Obviously the deck can't open that every time, so a couple of choices are there to enhance the ability to slow roll to Godrotter - Exploiter, Scrap and Cetugon rarely let you down and give you leeway over a host of decks. Pirate's Grotto, Enchinoderm and Thunders do help you dig into your Deck for the necessary cards and let you access extra protection to prevent your field being broken. 3 Lifeforce is obviously staple, but Hostile is @3 to really make your Declaration stick, and help Godrotter tank through Extortion/Scrap. I might swap them for Mirror Shot/Acid Spark for the guaranteed survival.

I'm trying a couple of options in the Extra, Witch is obvious for turning off Deceivers and Pteryx in those match-ups and searched by Maria. Only 1 Witch since Maria tutors it and it recurs itself. Raven and Blizzard comes in against Chaos, Blizzard also in against Mezzo or Antennae (or any other Deck that it might be good against). Abyss for Nox/Pteryx to turn off Uprise and Blizzards. Dome/Solemn World for Interdimensionals and others that may use Fields. Trumpets are something I had considered for the mainboard to make Godrot/Declaration even harder to break, but for now I'm going to try it in the side.

I think the Deck has a lot of potential if current trends continue, and if the meta does take on a faster pace then Declaration also has fantastic value.

Now, with blizzard getting the boot, i can see this deck becomes meta -relevant in the next format. 

3000 beater backed with lifeforce and declaration is scary, as you have said.

What's the best replacement for blizzard in the side deck for the next meta?

i think i'd try the 3rd trumpets and 3rd raven or swap them for 2 spike trap

will spike trap be effective at only 2?

yes

now that this deck is down to 1 Declaration, 1 Kotei, and 1 Lifeforce, is the deck dead or can it still get rolling?

Definitely not as good, but maybe teching Halt in here alongside something like Dylan's pot of duality might help.