Monks of the Way of the Contortionist have strived to emulate the serpentine motions of the flexing, coiling boa, possessing even amongst the most physically-adept martialists a sense of control over their physical structure that few can hope to rival. They are able to move in ways that belie their flesh and bone, seemingly able to flatten themselves through the bars of imprisonment, to whip and sway in a snakelike manner that befounds attackers and feints defenders. Most of all, though, they are known for their nigh-unbreakable holds and grabs, a curving, locking embrace that can stifle motion, pressure nerves, lock joints and, with the proper training and application of their more malleable bodies, break bones with but a graceful tightening of their muscles.

Boa Style

When you choose this Monastic Tradition at 3rd level, you begin to fine-tune your ability to move your muscles, your extremities, your very bones, until your body structure becomes flexible and capable of contorting to your will.

As a bonus action, you can make a special grapple check, using either Athletics or Acrobatics to initiate. The creature must be one size larger than you or smaller. If successful, you enter Boa Style, wrapping yourself around the creature. While grappled in such a way, the creature has disadvantage on attacks against you, and you employ a different set of Ki Powers than those typically afforded a Monk.

Constricting Bar

Immediately after you deal unarmed damage, you can spend a ki point attempt to further restrict the prey's range of motions, wrapping yourself around one of their extremities.

Arm Bar: If the target fails a Strength save, you tighten their arm's motions; they will have disadvantage on attacks until the end of your turn.

Leg Lock: If the target fails a Strength save, their legs seize beneath them as you pressure them. The target is knocked prone.

Weight Shunt: If the target fails a Strength save, they are pulled and swayed from their spot by your shifting gait. Force the target to move half your movement.

Tightened Coils

You can spend 1 ki point as a reaction to curl your form closer to your prey, using the creature you've grappled as cover. Until the start of your next turn, you are considered in half cover.

Contortionism

You gain proficiency in Athletics or Acrobatics. If the monk is grappled, they may spend half their movement to break free.

Cobra Style

At 6th level, you become more accustomed to bending your physical structure in unusual ways, swaying out of attacks like a cobra's gait before striking suddenly, when they overreach. When you use the Patient Defense Ki Power, when an enemy creature misses an attack, you may use your reaction to initiate a Boa Style grapple with advantage.

Malleable Form

Moving stealthily, through space that other creatures occupy, and other tight spaces do not interfere with your movement. In addition, gain expertise in the skill chosen for your Contortionism.

Anaconda Style

At 11th level, you've gained greater mastery over your unique grappling style, and become more capable of controlling your prey once they've fallen into your grasp. You gain these additional ki powers while in your Boa Style grapple.

Nerve Brace: The hold on the creature finds a sensitive place to add pressure to, locking the prey entirely. By spending three Ki points, they may put the target into a Nerve Brace. On a failed Constitution save, the creature becomes restrained until the end of their turn, where they may make another Constitution save. If they fail again, they are paralyzed until the end of their next turn.

Serpent's Den: An expert contortionist is never truly caught out, even when they have prey locked in their grasp. The Tightening Coils reaction now costs 2 Ki points, but your prey becomes three-quarters cover, and on a failed hit, the opponent must make a separate attack roll against your prey.

Jormungandr Style

At 17th level, you've mastered the art of contortionism to such a frightening extent, that to your prey, you seem to be capable of stretching your form unnaturally to contain even the largest of creatures.

Creatures more than a size larger than you may be put into a Jormungandr-style grapple, wherein you choose one of your three Boa Style Constricting Bars before initiating. For the duration of this limited grapple, the target creature still has half movement, and you may only perform the corresponding Bar by spending ki points. In addition, by spending a ki point at the start of your turn, you may change your positioning on the creature to employ a different Constricting Bar.

The Sleeping Serpent

By spending five ki points as an action during a Boa Style grapple, the monk may tighten and squeeze every ounce of their physicality around the prey's back and neck, attempting to crush their spine. If the target fails a Constitution save, it is reduced to 0 hit points. On a success, the target is stunned, and takes 5d12 force damage.