Blinker

Observation Lock. When any creature observes the Blinker, it freezes into a stone-like substance. Whilst observed, the Blinker is considered petrified. This ability is not voluntary and the Blinker is subject to this effect from any creature that uses eyes to see. Creatures that only use Blindsight or Tremorsense to see the Blinker do not trigger this. Whilst being observed, the Blinker is subject to the following conditions:

• It cannot move in any way by its own accord.
• It cannot take any actions except for its Extinguish or Blink. (It can still hold its action for when it isn't being observed).
• It cannot take bonus actions, or reactions that involve it moving.
• The Blinker's damage resistances become immunities and it gains resistance to all other forms of damage not listed.
• The Blinker is still aware of its surroundings and knows the direction it is being observed from.

Blind Speed. The Blinker can take the Dash action as a bonus action. Whilst dashing, the Blinker ignores difficult terrain.

Staring. For a creature to maintain looking at the Blinker requires it to not take its eyes off it, to not even blink. A creature can keep its eyes open for 1 + half its Constitution modifier rounds (minimum of 1 round). Once they have reached their maximum, the creature must roll a DC (10 + the number of rounds the creature hasn't blinked) Constitution saving throw. On a success, they keep their eyes open, on a failure the creature blinks. When a creature blinks it is considered blinded until that start of its next turn, resetting the number of rounds since the creature last blinked.

Eyes Open. If a creature is looking at the Blinker and uses its action to attack, the creature must roll a DC (10 + the number of rounds it hasn't blinked) Constitution saving throw. If the creature fails, the creature blinks and considered blinded until that start of its next turn, resetting the number of rounds since the creature last blinked.

False Appearance. While the Blinker remains motionless, it is indistinguishable from an inanimate statue.

Immutable Form. The Blinker is immune to any spell or effect that would alter its form.

Magic Resistance. The Blinker has advantage on saving throws against spells and other magical effects.

Magic Weapons. The Blinker's weapon attacks are magical.

Innate Spellcasting. The Blinker innate spellcasting ability is Wisdom. It can innately cast a number of spells, requiring no verbal, somatic or material components.

At will: spider climb

1/Day: darkness

Multiattack. The Blinker can use it Heavy Eyes. It then makes four attacks with its blades.

Blades. Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 15 (2d6 + 8) slashing damage. 

Heavy Eyes. All creatures within 120 feet of the Blinker must make a DC (10 + the number of rounds the creature hasn't blinked) Constitution saving throw. On a success, the creature keeps its eyes open. On a failure, the creature blinks and is considered blinded until that start of its next turn, resetting the number of rounds since the creature last blinked.

Extinguish (Recharge 5-6). The Blinker can attempt to extinguish all sources of light it can see within 120 feet. If the light source is magical, the Blinker must roll a Wisdom check, extinguishing the light on a success. The DC is 10 + the spells level, cantrips having a value of zero.

Quick Slash. When a creature attempts to attack the Blinker but blinks as it tries to hit, the Blinker uses the momentary blindness and obsucred view to make one attack against the creature with its Blades.