Corrupt Basilisk

Petrifying Gaze. If a creature starts its turn within 30 feet of the basilisk and the two of them can see each other, the basilisk can force the creature to make a DC 14 Constitution saving throw if the basilisk isn't incapacitated. On a failed save, the creature magically begins to turn to stone and is restrained. It must repeat the saving throw at the end of its next turn. On a success, the effect ends. On a failure, the creature is petrified until freed by the greater restoration spell or other magic.

A creature that isn't surprised can avert its eyes to avoid the saving throw at the start of its turn. If it does so, it can't see the basilisk until the start of its next turn, when it can avert its eyes again.

Illusory ability. The corrupt basilisk has gained the ability to disguise itself using innate psionic powers. It can make itself look like any object to lure a wary traveler closer. A DC 14 perception check made at a distance can determine something being off with the illusion.

Multiattack. The corrupt basilisk makes one bite attack and one claw attack

Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 16 (4d6 + 3) piercing damage plus 7 (2d6) poison damage.

Claw. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 7 (1d8+3) slashing damage.

Stone's return. As a bonus action the corrupt basilisk can command one of its petrified prey to turn back for an instant and let it attack. Once a petrified prey is used like this, it cannot be used again. The basilisk has 4 melee attackers, 2 ranged attackers, and one mage available.

Melee. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 7 (2d6+1) slashing damage

Ranged. Ranged Weapon Attack: +4 to hit, reach 60 ft., one target. Hit: 5 (1d8+1) piercing damage.

Mage. Ranged Spell Attack: Lightning Bolt with a spell save of 14.

Stone Defense. When dealt piercing, slashing or bludgeoning damage the corrupt basilisk can use it's reaction to briefly turn its skin to stone, halving all damage done