When you are hit by a ranged weapon attack, you can use your reaction to attempt to catch the projectile. Reduce the damage by an amount equal to your Monk level + one roll of your Martial Arts die + your Dexterity modifier. If you reduce the damage to zero, you catch the projectile in a free hand.
If you catch the projectile, you can make a ranged (20/60) Martial Arts attack with that projectile as part of the same reaction. You are proficient with this ranged weapon attack.
Beginning at 11th level, you can spend 1 Ki Point to use this reaction whenever you are hit by a spell attack.
When you hit a creature with a melee Martial Arts attack, you can spend 1 Ki Point to strike with relentless force, forcing it to make a Constitution saving throw. On a failed save, the creature is stunned until the beginning of your next turn.