Monks of the Serpent's Coils look at other martial disciplines taught in monasteries, as well as the gruesome reality of a tavern brawl, and they realised there is a great discrepancy between the two. As such, they have decided to take a more tricky approach to combat, manipulating not only their environment, but their enemies and allies alike to become just as menacing when fighting a common thug who spat in your drink as they do fighting peer-to-peer with the deities of the Nine Realms.

Menace in the Streets.

 

You have been attacked in a pub enough times to make a chair in your hands just as deadly as a greatsword in a ruffian's hands. When you choose this tradition at 3rd level, you gain the following benefits:

• You become proficient in Athletics, if you weren't already. If you were already proficient in Athletics, you may double your proficiency modifier.
• Whenever you use an improvised weapon, you may treat it as if it were a Monk weapon, even if it has the two-handed or heavy properties.

Snake's Trickery

Additionally, starting at 3rd level, you have gained a better understanding of the terrain and how to make it fight for you. You gain access to "terrain actions", fueled by your Martial Arts die. The Terrain Actions you can execute depend on where you and/or your target are situated.

Saving Throws. Some of your terrain actions require your target to make a saving throw to resist the maneuver’s effects. The saving throw DC is calculated as follows:

Terrain save DC = 8 + your proficiency bonus + your Dexterity modifier.

A few examples of terrain actions follow, but it is heavily encouraged to discuss other such actions with the DM.

Clothesline

If a creature moves into your melee range, and out of it again from the same effect (be it out of their own will, or due to knockback from something like the Thunderwave spell), you can expend your reaction to make a melee attack against the creature's AC. On a hit, the creature's movement speed is reduced to zero, and they become prone, until the end of their next turn.

Cornered

If a creature is standing less than five feet away from a wall, you can attempt to press them up against it. When you take the attack action on your turn, you can forego one of your attacks to make an athletics check against the creature's AC. On a success, you shove them against the wall, dealing two Martial Arts dice worth of bludgeoning damage and forcing the creature to make a dexterity saving throw, or fall prone from the disorienting impact.

Defenestrate

When a creature is standing less than five feet away from a window, you can attempt to throw them out of it. When you take the attack action on your turn, you can forego one of your attacks to grapple the creature. On a success, you throw them out of the window.

In the Eyes

If you and a creature are both standing on dirt, sand, or other such "fine terrain" (DM's discretion) or inside of a liquid, you can throw a handful in your opponent's eye. Alternatively, if you have something similar to these in your inventory (like a bag of sand, a waterskin filled with wine or a vial of acid), you can choose to throw this instead. When you take the Attack action on your turn, you can forego one of your attacks to force the target to make a Dexterity saving throw, or be blinded until it takes an action to clear its eyes.

Leg Sweep

When you hit a creature with an Unarmed Strike and you are on even terrain to them, you can force the creature to make a dexterity saving throw. On a failed save, they become prone.

Anaconda's Resillience

Beginning at 6th level, you can empower your body's raw power using Ki. Whenever you need to make a strength check or saving throw, you can add an amount of Ki points equal to half your Monk level, rounded down to a failed check/save, potentially turning it into a success.

Anaconda's Brutality

Furthermore, starting at level 6, if you successfully grapple a creature, you may use a bonus action and an amount of Ki equal to half your Monk level to jump into the air (provided there is no ceiling to stop you) and slam them against the ground. The height you jump increases by 5ft per Ki point, and the damage is equal to your Martial Arts Die, times the amount of Ki spent.

Cobra's Venom

Starting at 11th level, you become able to unleash Ki-empowered strikes in... less than honorable ways.
Whenever you make an attack action, you can exchange one of your attacks to hinder your opponent in one of the following ways: 

Bite Attack
You bite a creature in their hide, infecting their body with your Ki not unlike a virus. You can expend two Ki points to force the target to make a Constitution saving throw, or take 4d6 Poison damage, and become Poisoned until they take a short rest. This effect bypasses resistances and immunities to the Poison damage type and the Poisoned condition.

Spit
You, unceremoniously, spit in an opponent's face. Aside from your saliva being ki-empowered, it's incredibly disgusting. Make a ranged attack against your opponent. On a hit, they must make a constitution saving throw, or take 4d6 Acid damage, becoming blinded for a number of turns equal to your Martial Arts die (so 1d8 turns at level 11-16, and 1d10 turns at levels 17 and above).

Once you use either of these abilities, you need to finish a short rest before you can use either one of them again.

Anaconda's Grasp

Furthermore, starting at 11th level, your ki-empowered body becomes capable of subduing even grander foes.

You become able to grapple creatures that are up to two sizes larger than you by expending a ki point.

Subdue the Prey

At 17th level, you start to contemplate that all this senseless violence and brutality is a little too much to handle for you. As such, you spend your time to developing a "swift and painless" technique to incapacitate your foes.

Whenever you succeed on an Athletics check to grapple a creature, you can force the creature to make a constitution saving throw. The grappled creature has a number of turns equal to half the result of this check, rounded down, to escape your grapple. If the current grapple between you and the creature has not yet ended when the creature has had the full amount of turns, they become incapacitated. Alternatively, you can choose to make a strength check to snap its neck, killing it instantly. The strength check is equal to the creature's challenge rating, plus the amount of sizes the creature is larger than you.