ALL CREDIT TO u/IAmTheOoga. Check out the other 2 versions (CR 8 & CR 15) on u/IAmTheOoga's reddit page or in my homebrew creations.

Legendary Resistance (3/Day). If the Inligulae fails a saving throw, it can choose to succeed instead.

Timeline Flux. At the start of each of this creature’s turns, a random effect occurs rolled on a d12 from the following table. Whenever it suffers a critical hit, the next roll on the table is made with disadvantage.

Acausal. The Inligulae is immune to time-related spells and effects.

Die Another Day. Upon being reduced to 0 HP, the Inligulae may continue fighting for 1d6-1 more rounds of combat, each time with a random percentage of its max HP. Reducing it to 0 HP again will end this effect. If the Inligulae manages to heal 40 or more HP during these rounds, it will have its HP reset to 40 after this effect ends. The Inligulae cannot use this feature again until the next dawn.

Persistence. Whenever another creature’s turn starts or they begin movement after stopping, their location at that moment is marked down. Instead of attacking enemies directly, some abilities allow the Inligulae to attack them through these marks. Attacked marks disappear after taking damage.

Worm-Scream. The Inligulae’s attacks deal an 2d6 additional psychic damage. This extra damage is included in the descriptions of each attack.

Inverted Timeflow. At the start of its turn after Timeline Flux, the Inligulae heals back 1d8+3 HP. It can choose not to activate this effect in order to halve the duration of any effects or conditions currently applied to it. In addition, the Inligulae can take the Disengage action as a bonus action.

Multiattack. The Inligulae makes 3 Past-Ripper attacks, or 2 Past-Ripper attacks and one Future-Breaker attack. If another ability is used, one Past-Ripper attack may be made as a bonus action.

Past-Ripper. Melee Weapon Attack: +13 to hit, reach 10 ft., single space target. Each creature in the target space takes 3d6+6 slashing damage plus 2d6 psychic damage, plus an extra 1d6 added on for every instance of the same creature’s marks within the targeted space. The Inligulae can opt to target marks with this action.

Future-Breaker. Melee Weapon Attack: +13 to hit, reach 10 ft., two adjacent spaces target. The next enemy to enter the targeted spaces immediately receives the attack, taking 4d8+6 bludgeoning damage plus 2d6 psychic damage. This action cannot target marks.

Tesseract (Recharge 4-6). All creatures within a 25 ft. cube centered 15 ft. in front of the Inligulae must make a DC 20 Intelligence saving throw. On failure, a creature takes 6d8 force damage, or half as much on a successful one. If the cube is centered on a creature, that creature must also make a DC 20 Dexterity saving throw or take an additional 2d8 force damage and be moved 1d6 turns forwards in time, at which point they will reappear and may take their turn unless a new round has begun, resetting them back to initiative. For every turn the creature is displaced, its current HP is modified by 1d12-7 added on (producing postitive (healing) or negative (damage) modifiers). This action cannot target marks.

Time Loop (1/Day). For the next 2d6 rounds, every other round players must end their turn on the same space as one of their marks or take 7d6 necrotic damage. If the players take the same action (not including movement) they did on their last turn, they may add 1 to the value of any die rolled on their turn. While this ability is active, the Inligulae heals 10 HP at the start of each of its turns. When this ability ends, the Inligulae is stunned until the end of its turn.

Temporal Deflection. When the Inligulae is targeted for an attack and there is a mark between it and the source of the attack, it can make a DC 15 Dexterity saving throw in order to make the attack remotely target the owner of the mark instead of it. On a failure, the Inligulae heals 10 HP back after taking damage.

Convergence. When a creature ends its turn on the same space as a mark, the Inligulae can force them to make a DC 20 Constitution saving throw. On a failure, both that creature and the owner of the mark take 1d4+11 force damage, have their AC reduced by 2 and have their movement slowed by 10 ft until the end of their next turn.

The Inligulae can take 3 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature's turn. The Inligulae regains spent legendary actions at the start of its turn.

Past Ripper. The Inligulae makes a Past Ripper.

Future Breaker. The Inligulae makes a Future Breaker attack.

Charge. The Inligulae moves up to its speed.

Tesseract (Costs 2 Actions). The Inligulae uses its Tesseract action if it is recharged.

Wormhole (Costs 2 Actions). The Inligulae selects up to 4 spaces within 30-10 feet. Whenever a creature other than the Inligulae enters these spaces, they are teleported to another one at random and may continue their movement from there. Upon passing through, they must make a DC 20 Intelligence save or become stunned until the start of their next turn. Upon passing the save, they may instead take an additional action immediately. If a creature ends their turn on one of the spaces, they take 2d6 force damage and have disadvantage on all saves until the end of their next turn.

Sever Timeline (Costs 3 Actions, 1/Day). The Inligulae makes 6 predictions as to actions that will occur in the next 2 rounds. It cannot make predictions solely targeting itself. The predictions can be any of the following:

• A specific creature will either land or miss an attack, pick one

• A specific creature will either pass or fail a save, pick one

• A specific creature will receive healing

• Any creature will cast a spell of a certain level

• A specific creature will move in a certain direction relative to it

• A specific number will be rolled by any creature

• A specific creature will not attack on their turn

• A specific creature will take more than 15 damage

The party will be informed of 1d4 of the predictions made. If 3 or more of the predictions come true, all creatures other than the Inligulae take 20 psychic damage plus 20 force damage, and have disadvantage on all attack rolls until the end of their next turn. In addition, the Inligulae may outline a series of future events outside of combat and the current encounter, and remove them from the realm of possibility. This should not make the success of the party’s quest impossible and make happy endings unachievable, but should have emotional weight and noticeable consequences.

If 3 predictions do not come true, then the Inligulae heals 12 HP for every prediction that did come true, and another 1d6+1 for every prediction shown to the party.

“Listen. It’s not worth it. Go the hard route, put in the effort, fix things without bending time. Even if you manage to survive the worm, it’s still not worth the risk. You want to know what the thing did?

We had it cornered, striking out at it faster than it could undo our blows. Pretty soon, we’d be out of that weird in-between space. But our mistake was thinking that just because the thing didn’t care if it died, it couldn’t get mad.

So it kneaded time like dough, and showed us a future. A good future. Thelembraun was able to fix his mistakes and document the forgotten histories, Drauman rallied his people and reclaimed their city, and Elsza’s father finally recognized her prowess. And me? I saw myself finally settle down back at home, get married, and die old and happy. It was everything we could have wanted.

And then it took that future it showed us, and ate it.”

- Teryll the Solitary