Beholder Parasite

Parasitic. While attached to a creature, when the parasite takes damage, it causes its host to take an equal amount of damage to the damage the parasite takes. The parasite also share any resistances, immunities and vulnorabilities the host has.

Tunneler. The Parasite can burrow through solid rock at half its burrowing speed and leaves a 4-inch-radius tunnel in its wake.

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one creature. Hit: 10 (2d6 + 3) piercing damage, and if the target is Large or smaller, The target, must succeed a DC 17 Strength check or have the parasite attache to it. While attached, the cloaker can make this attack only against the target and has advantage on the attack roll. A creature, including the target, can take its action to detach the cloaker by succeeding on a DC 20 Strength check. if the host is reduced to 0 hit point while the parasite is attached, it permanelty fuses to the hosts' body, only being able to be removed by a Greater Restoration as long as it is cast within 100 days of the parasite fusing.

Paralyzing Ray (Recharge 5-6). The beholder shoots a magical eye ray at a target it can see within 120 feet of it. The targeted creature must succeed on a DC 16 Constitution saving throw or be paralyzed for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.