It is said Master Ploopploopleen developed the way of the Pleen during his battles with mindflayer slavers in the Underdark. This bizarre martial art focuses on enhancing it's users abilities with ancient Kuo-toa transformation magic. Monks who practice the Way of the Pleen can enhance different parts of their body to aid them in combat and while proselytizing by summoning spectral claws, a fun hat , and even a slick body. It is said in hallowed tomes that those who master the Way of the Pleen can even take on the most holy of forms, a Ploopploopleen Leviathan. This monstrous fish is especially adept at destroying ships and other structures. Master Ploopploopleen used this gargantuan form to destroy a mindflayer colony and it's elder brain, freeing the Kuo-toa from slavery. Knowledge of the Way of the Pleen is strictly guarded, and is only taught to those in Ploopploopleen's blood line who have achieved the rank of Ba-Poolgol or higher. 

Claws of Blipdoolpoolp

3rd-level Way of the Pleen feature

Your mastery of your ki allows you to summon a portion of your inner Ploopploopleen. As a bonus action, you can spend 1 ki point to summon the claws of the Sea Mother. When you do so, each creature of your choice that you can see within 10 feet of you must succeed on a Wisdom saving throw or take psychic damage equal to two rolls of your Martial Arts die.

For 10 minutes, these spectral lobster claws hover near your shoulders or surround your arms (your choice). You determine the claws’ appearance, and they vanish early if you are incapacitated or die. While the spectral claws are present, you gain the following benefits:

• You can use your Wisdom modifier in place of your Strength modifier when making Strength checks with the claws to initiate a grapple.
• You can use the spectral claws to make unarmed strikes.
• You can use your reaction to deflect a spell with your claws when you are hit by a ranged spell attack. When you do so, the damage you take from the attack is reduced by 1d10 + your martial arts die + your Wisdom modifier + your monk level. If you reduce the damage to 0, you can deflect the ranged spell attack back at it's caster. If you deflect a spell in this way, you can spend 1 ki point to make a ranged spell attack with the magic energy you just deflected, as part of the same reaction. You make this attack using your spell attack modifier. On a hit the target takes half the total damage from the original spell. 
• The unarmed strikes you make with the claws can use your Wisdom modifier in place of your Strength or Dexterity modifier for the attack and damage rolls, and their damage type is force.

Visage of the Plope

6th-level Way of the Pleen feature

You can summon the visage of a Plope Hat on your head.  As a bonus action, or as part of the bonus action you take to activate the Claws of Blipdoolpoolp, you can spend 1 ki point to summon the visage of a lobster Plope Hat. It vanishes early if you are incapacitated or die.

A spectral lobster head covers your face like a helmet or mask. You determine its appearance.

While the ceremonial lobster hat is present, you gain the following benefits.

Eyes of the Kuo-toa. You can see normally in darkness, both magical and nonmagical, to a distance of 120 feet.

Wisdom of the Plope. You have advantage on Wisdom (Insight) and Charisma (Persuasion) checks.

Voice of Bli Bli. When you speak, you can direct your words to a creature of your choice that you can see within 60 feet of you, making it so only that creature can hear you. Alternatively, you can amplify your voice so that all creatures within 600 feet can hear you.

Body of the Pleen

11th-level Way of the Pleen feature

When you have both your Blibdoolpoolp claws and Plope visage summoned, you can cause the body of the Pleen to appear (no action required). This slick-wet fishy body covers your physical form like a suit of armor, connecting with the claws and Plope hat. You determine its appearance.

While the Pleen body is present, you gain the following benefits.

Deflect Energy. When you take acid, cold, fire, force, lightning, or thunder damage, you can use your reaction to deflect it. When you do so, the damage you take is reduced by 1d10 + your Wisdom modifier (minimum reduction of 1).

Empowered Claws. Once on each of your turns when you hit a target with the Claws of Blipdoolpoolp, you can deal extra damage to the target equal to your Martial Arts die.

Slick Retreat. You leave a viscous, wet trail behind you when you move. While Body of the Pleen is active, you can teleport up to 15 feet as a bonus action to an unoccupied space you can see on your slimy trail. You must have occupied that space at some point during the current turn. 

Ploopploopleen Leviathan

17th-level Way of the Pleen feature

Your connection to your Ploopploopleen ancestor is complete, allowing you to unleash your full potential. As a bonus action, you can spend 5 ki points to summon the claws, visage, and body of your Ploopploopleen Leviathan form and awaken it for 10 minutes. While in this form you grow to gargantuan size and your weight is multiplied by your monk level.  This awakening ends early if you are incapacitated or die.

While your Leviathan form is awakened, you gain the following benefits.

Ploopploopleen Hide. You gain a +2 bonus to Armor Class.

Claw Barrage. Whenever you use the Extra Attack feature to attack twice, you can instead attack three times if all the attacks are made with your Blipdoolpoolp claws.

Siege Monster. While in Ploopploopleen Leviathan form you deal double damage to objects and structures.