Way of the Viper.

Monks who follow the Way of the Viper embody the serpentine grace and cunning of their namesake. Masters of fluid movement and elusive strikes, these monks are as swift as striking vipers, their bodies flowing seamlessly like a coiled serpent ready to strike. With a deep understanding of timing, distance, and precision, they navigate the battlefield with unmatched reactivity and unmatched elusiveness.

Level 3 Features:

Serpentine.

Starting when you choose this tradition at 3rd level, you take on certain snakelike attributes to empower your other monk features. You gain the following benefits:
Serpent Strike: The first unarmed strike of your Flurry of Blows that hits a creature becomes a Serpent Strike: a creature hit by a Serpent Strike takes extra poison damage equal to your Wisdom modifier (minimum of 1) and must make a Constitution saving throw against your ki save DC. On a failed save, the creature is poisoned until the start of your next turn. At 17th level, this extra poison damage increases to 1d10 + your Wisdom modifier.
Snake's Movement: Moving while prone does not cost you extra movement, and standing up from prone uses only 5 feet of your movement.
Snatching Serpent: When a missile that you can see comes within 10 feet of you, you can use your Deflect Missiles reaction to move up to 10 feet to intercept it, provided your speed is not 0; this movement does not provoke opportunity attacks. When you do, the damage taken by the missiles target is reduced by 1d10 + your Dexterity modifier + your monk level. If you reduce the damage to 0, you can catch the missile as normal.

Level 6 Feature:

Shed Skin.

By 6th level, you can escape all manner of illnesses and bindings. At the start of your turn, if you are blinded, deafened, grappled, paralyzed, poisoned, or restrained, roll a d6. On a 6, those conditions end on you. The minimum number you need to roll on the d6 to end those conditions is reduced when you reach certain levels in this class: 11th level (5 or 6) and 17th level (4, 5, or 6).
In addition, if a creature hits you with an opportunity attack, you can use your reaction to cause the attack to miss. You can not do so again until you finish a short or long rest.

Level 11 Feature:

Slither.

By 11th level, your movements are entirely silent. You have advantage on Dexterity (Stealth) checks, and moving through another creatures space while prone does not cost you extra movement. In addition, being prone no longer imposes disadvantage on your attack rolls.

Impossible Venom.

Also at 11th level, your own immunity to poison allows you to infuse your poisons with ki, subverting the defenses of your enemies. Your attacks and effects ignore a creatures resistance or immunity to poison damage, as well as its immunity to the poisoned condition.

Level 17 Feature:

Lunging Strikes.

By 17th level, your movements and strikes are impossibly quick and precise. A creature provokes an opportunity attack from you when it enters a space within 10 feet of you, as well as when it misses with an attack from within that range; you can immediately move up to 10 feet towards the target, without provoking opportunity attacks, as part of this opportunity attack. Furthermore, whenever you make an opportunity attack using an unarmed strike, it becomes a Serpent Strike.
Once per turn, if you have already taken your reaction, you can spend 2 ki points to take an additional reaction. You can use only one reaction per triggering effect.