Slither. If the titanoboa hasn’t eaten a Huge creature in the last 24 hours, it can move through a space as narrow as 10 feet wide without squeezing, or 5 feet while squeezing.

Sparkling Scales. The titanathema’s scales refract light iniridescent cascades that are hypnotic to gaze upon. If the titanathema is in bright light, a creature within 30 feet that looks at it must make a successful DC 17 Wisdom saving throw or be stunned until the end of its next turn. Unless surprised, a creature can avoid the saving throw by choosing to avert its eyes at the start of its turn. A creature that averts its eyes can’t see the titanathema until the start of its next turn, when it can choose to avert its eyes again. If the creature looks at the titanathema in the meantime, it must immediately make the saving throw.

Innate Spellcasting (Anathema Form Only). The titanathema's innate spellcasting ability is Charisma (spell save DC 17). It can innately cast the following spells, requiring no material components:

At will: animal friendship (snakes only)

3/day each: darkness, entangle.fear, haste, suggestion, polymorph1/day: divine word

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

Ophidiophobia Aura. Any creature of the titanathema's choice, other than a snake or a yuan-ti, that starts its turn within 30 feet ofthe anathema and can see or hear it must succeed on a DC 17 Wisdom saving throw or become frightened of snakes and yuan-ti. A frightened target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a target's saving throw is successful or the effect ends for it, the target is immune to this aura for the next 24 hours.

Shapechanger. The titanathema can use its action to polymorph into a Huge giant constrictor snake, or back into its true form. Its statistics are the same in each form. Any equipment it is wearing or carrying isn't transformed.

Six Heads. The titanathema has advantage on Wisdom (Perception) checks and on saving throws against being blinded, charmed, deafened, frightened, stunned, or knocked unconscious.

Multiattack. The titanathema makes one bite attack and oneconstrict attack.

Bite. Melee Weapon Attack: +13 to hit, reach 10 ft., one target.Hit: 21 (3d8 + 8) piercing damage. If the target is a Huge or smaller creature, it must succeed on a DC 18 Dexterity saving throw or be swallowed by the titanathema. A swallowed creature is blinded and restrained, has total cover against attacks and other effects outside the snake, and takes 21 (6d6) acid damage at the start of each of the titanathema’s turns. If thetitanathema takes 30 damage or more on a single turn from a creature inside it, the titanathema must succeed on a DC 15 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, which fall prone in a space within 10 feet of the titanathema. If the titanathema dies, a swallowed creature is no longer restrained by it and can escape from the corpse by using 20 feet of movement, exiting prone.

Constrict. Melee Weapon Attack: +13 to hit, reach 15 ft., one target. Hit: 27 (3d12 + 8) bludgeoning damage, and the target is grappled (escape DC 18). Until this grapple ends, the target is restrained,and the titanathema can’tconstrict another target.