"Words describing it fail. Pages relating it shrivel. Tales recounting it end."
Summon Monstrous Creatures of the Dark Depths to Crash through your Unsuspecting Opponent's Defenses.
The win condition for this deck is simple, smash through the enemy's defense with huge creatures that are Unblockable. The main method of getting the heavy hitters out quickly is Quest for Ula's Temple.
I have seen iterations of this deck before and they all seem to follow the same formula, Quest for Ula's Temple ASAP using Clockspinning or Proliferate like Tezzeret's Gambit. For this casual budget build, I've omitted some pricier additions to the deck and added some more splendid jank.
My deck is much the same, with a couple of twists.
I run 30 creatures and 16 lands in this deck. Because you should never need more than 1 land. If you can ever hardcast Inkwell Leviathan... well you're never going to hardcast Inkwell Leviathan.
Scry is important in this deck, not only to find Quest for Ula's Temple if you didn't get in the first hand (WHY DIDN'T YOU MULLIGAN), but also to set up the creatures for each draw so that you add counters to it. Sage of Epityr, Mystic Speculation, Brainstorm, Halimar Depths and Temple of Deceit all provide Scry (or at least let you look at your topdeck).
I've splashed Black. I've only done this for Disciple of Deceit. Disciple is hard to consistently get out, especially with 16 lands. But it can tutor the Temple, and damn that flavor fits.
Dizzy Spell is there for its Transmute, which can grab Quest for Ula's Temple, or any other CMC's.
Once Quest for Ula's Temple is out, Clockspinning can add counters.
The Leviathans that will win the game for you are Inkwell Leviathan, Stormtide Leviathan, Tromokratis, and Deep-Sea Kraken. Grozoth is primarily there to stack your hand with Inkwell Leviathans, and Trench Gorger thins your deck of lands once Ula's Temple is online.
Kraken Hatchling helps stall early aggression, Cursecatcher can can help protect your temple early on.
Thassa, God of the Sea gives both Scry and Unblockable, although at cmc, it can be difficult to play, but it works splendidly when you can play it.
Check out my Casual Meta Decks!
Just a Note, I make the majority of my decks with casual play in mind within my own playgroup. These decks are intended to be balanced within my own meta and fairly budget conscious, which may be why some obvious cards are excluded