Blind Screecher

Blindness. Blind Screechers have no eyes, using a form of echolocation to see and locate any object around them. 

Echolocators. Blind Screechers use echolocation to see, if they become deafened they cannot use blindsight.

Keen Hearing. Blind Screechers have advantage on Wisdom (Perception) checks that rely on hearing.

Darkness dwellers. The Blind Screechers are born and live in darkness, they are immune to any form or darkness normal or magic. They have also developed deep sense of the surrounding vibrations, giving them a very large tremorsense that extends it's senses to long distances; they can sense vibrations of surfaces they are on in a 60 ft radius.

Silent Hunters. Blind Screechers prefer a sneaky approach to attack their prey, always attacking from the shadows. On the first turn, they have a 1d4 bonus to attacks against those with lower initiative.

Slimy Creatures. Blind Screechers have a slimy and flexible skin, making them almost impossible to capture. Any grapple attempt done against them has to pass a strength or dexterity roll, players choice, with disadvantage to succeed and Blind Screechers have advantage in any attempt to escape from a grapple.

Multiattack. Blind Screechers can make three attacks.

Claw  Melee Weapon Attack. +8 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 5) slashing damage.

Bite Melee Weapon Attack: +9 to hit, reach 5 ft., one creature. Hit: 11 (2d6 + 5) piercing damage. If it hits, the target makes a consitution saving throw DC 18 or become poisoned

Horrible Screech(Recharge 5–6). Blind Screechers can use their screech attack instead of one of their attacks. They make a horrendous and potent sound similar to metal scratching that surges outward from them in a 60-foot emanation; each creature in the emanation makes a constitution saving throw with DC 17. On a failed save a target takes 5d6 thunder damage and becomes deafened, and if the save is failed for 10 or more it becomes stunned until the end of their next turn.  On a successful save, a target takes half as much damage only.

Spellcasting. Blind Screechers can cast as innate abilities without the need of any components some spells, and can cast them instead of one of the attacks; they are considered level 5 casters.

3/day from the list: darkness, thunderwave

2/day from the list: invisibility, silence

1/day: thunder step

At will thunderclap

Darkness Steps. While entirely within Dim light or Darkness, Blind Screechers can use a Bonus Action to teleport up to 60 feet to an unoccupied space they can see that is also in Dim Light or Darkness.