Dimensional Filament
The Voidfang Needlebeast exists in multiple dimensions at once. It can move through any physical barrier, and attacks made against it have disadvantage unless the attacker can see into the Ethereal Plane.

Multiattack.
The Needlebeast makes three Phase Pierce attacks.

Phase Pierce.
Melee Weapon Attack: +16 to hit, reach 5 ft., one target.
Hit: 38 (8d6 + 10) piercing damage. If the target is a creature, it must make a DC 21 Constitution saving throw or become disoriented, taking disadvantage on attack rolls and ability checks until the end of its next turn.

Event Horizon Swarm (Recharge 5-6)
The Needlebeast tears a hole through spatial reality. It briefly exists in 10 locations simultaneously within 60 feet. Choose up to 5 creatures the beast can see. Each must make a DC 22 Dexterity saving throw or take 72 (16d8) piercing damage. On a success, they take half damage. The Needlebeast then returns to its original space. This movement does not provoke opportunity attacks.

Void Blink.
The Needlebeast teleports to an unoccupied space within 60 feet. Until the start of its next turn, it gains resistance to all damage.

Quantum Evasion.
When hit by an attack, the Needlebeast can vanish momentarily, forcing the attacker to reroll the hit with disadvantage.

Spacetime Ripple.
When a creature moves within 10 feet, the beast can cause a spatial shiver, forcing the creature to succeed a DC 18 Constitution saving throw or be slowed until the end of its next turn.