Blue Serpent Ninja

Earth Glide. The Blue Serpent Ninja can burrow through nonmagical earth and stone. While doing so, the Blue Serpent Ninja doesn't disturb the material material it moves through. 

Multiattack. The Blue Serpent Ninja makes two melee attacks or three ranged attacks. 

Trident. Melee or Ranged Weapon Attack: +3 to hit, reach 5 ft. and range 20/60 ft., one target. Hit: 5 (1d6 +1) piercing damage or 6 (1d8 + 1) piercing damage if used with two hands to make a melee attack.  

Water Missile. Ranged Weapon Attack: +5 to hit, range 15/30 ft., one target. Hit: 6 (1d4 + 3) bludgeoning damage. If a creature is hit by two water missile attacks in the same round, their walk speed decreases by 10 until the end of their turn. 

Water Pillar (2/Day). The Blue Serpent Ninja creates a 15 foot wide and 80 foot tall pillar of water centered on their position. This pillar provides disadvantage against non magical ranged weapon attacks and total cover for creatures behind it. If a hostile creature wishes to pass through the pillar of water they must succeed on a DC 15 Strength check or be knocked back 10 feet from the pillar on a failure. The Blue Serpent Ninja can keep the pillar active as long as it spends it action to continue concentrating on the ability. The ability immediately ends if the Blue Serpent Ninja loses concentration or dismisses the ability as a free action.