Tesseract

Large construct, unaligned


  • Armor Class 18 (natural armor)
  • Hit Points 210 (20d10 + 100)
  • Speed 15 ft.

STR DEX CON INT WIS CHA
10 (+0) 10 (+0) 20 (+5) 10 (+0) 20 (+5) 1 (-5)

  • Saving Throws Con +10, Wis +10
  • Skills Insight +10, Perception +10, Stealth +5
  • Damage Resistances cold, fire, lightning, thunder; bludgeoning, piercing, and slashing from nonmagical attacks
  • Damage Immunities acid, necrotic, poison
  • Condition Immunities blinded, charmed, deafened, exhaustion, frightened, grappled, petrified, poisoned, prone
  • Senses blindsight 60 ft. (blind beyond this radius), passive Perception 20
  • Languages
  • Challenge 15 (13,000 XP)

Amorphous. While the tesseract generally appears as a solid geometric object, it can change its shape and may take up any available space up to 20ft in diameter. Any creatures that enter the space must make a DC 18 Wisdom saving throw or be banished to the tesseract's favored plane.

Banishing Touch. Any creature that touches or is touched by the tesseract must make a DC 18 Wisdom saving throw or be banished to the tesseract's favored plane. This ability cannot be used while the tesseract is in its attack form.

Inscrutable. The tesseract is immune to any effect that would sense its emotions or read its thoughts, as well as any divination spell that it refuses. Wisdom (Insight) checks made to ascertain the tesseract's intentions or sincerity have disadvantage.

Favored Plane. Once per day, the tesseract determines a random world or plane of existence (DM's discretion). Whenever the tesseract banishes creatures, they are taken to this location. This plane or location cannot be the current world the creatures are on, nor can it be their home plane or world (if different).

Force Field. While the tesseract is in its shield form, a shimmering wall of force surrounds it, giving it +5 to its AC and all attacks against it are made with disadvantage.

Innate Spellcasting. The tesseract's innate spellcasting ability is Wisdom (spell save DC 18, +10 to hit with spell attacks). It can innately cast the following spells, requiring no material components:

Cantrips (at will): Acid Splash, Dancing Lights, Lightning Lure, Mind Sliver, Thunderclap
1st level (4 slots): Chromatic Orb, Expeditious Retreat, Magnify Gravity, Thunderwave
2nd level (3 slots): Shatter, Silence, Tasha's Mind Whip
3rd level (3 slots): Fireball, Lightning Bolt, Pulse Wave


4th level (3 slots): Dimension Door, Gravity Sinkhole, Otiluke's Resilient Sphere
5th level (2 slots): Synaptic Static, Temporal Shunt
6th level (1 slot): Disintegrate
7th level (1 slot): Prismatic Spray
8th level (1 slot): Reality Break
9th level (1 slot): Gate

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

Actions

Multiattack. While in its attack form, the tesseract may make two psychic smash attacks.

Psychic Smash. While in its attack form, the tesseract may make a psychic attack against any creature within range.

    Melee Spell Attack: +10 to hit, reach 10 ft., one target. Hit: 41 (8d8 + 5) damage.

Lure. While in its lure form, the tesseract can expend an action to lure creatures towards it. Every Humanoid and giant within 300 ft. of the tesseract that can see the tesseract must succeed on a DC 18 Wisdom saving throw or be Charmed until the end of their next turn. The tesseract must take a Bonus Action on its subsequent turns to continue the lure. It can cancel the lure at any time. The lure ends if the tesseract is Incapacitated.

    While Charmed by the tesseract, a target is Incapacitated and ignores other charm effects. If the Charmed target is more than 5 ft. away from the tesseract, the creature must move on its turn toward the tesseract by the most direct route. It doesn't avoid Opportunity Attacks, but before moving into damaging terrain, such as lava or a pit, and whenever it takes damage from a source other than the tesseract, a target can repeat the saving throw. A creature can also repeat the saving throw at the end of each of its turns. If a creature's saving throw is successful, the Effect ends on it.

    A target that successfully saves is immune to the tesseract's lure for the next 24 hours.

Regenerate. While the tesseract is in its shield form, it may expend an action to regain 2d8 +10 hit points if it has at least 1 hit point.

Legendary Actions

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

Darkness. The tesseract may use one of its legendary actions to change its patterned coloring to pure black. No light can reflect off this darkness and all creatures within visible range must make a DC 18 Wisdom saving throw or be stunned. At the end of the creature's turn, they may repeat the Wisdom saving throw.



    While darkness is in effect, attacks against the tesseract have disadvantage.

Extra Attack. While in its attack form, the tesseract may make a psychic smash attack against a creature within range.

Hypnotic Pattern. The tesseract changes its surface appearance to create a twisting pattern across the entire shape. The pattern lasts until the end of its next turn. Each creature in the area who sees the pattern must make a DC 18 Wisdom saving throw. On a failed save, the creature becomes charmed for the duration. While charmed by this spell, the creature is incapacitated and has a speed of 0.

    The effect ends for a creature if it takes any damage or if someone else uses an action to shake the creature out of its stupor.

    While hypnotic pattern is in effect, attacks against it gain disadvantage.

Shape Change. The tesseract changes its shape to one of three basic shape types, though the shapes themselves may vary. Each shape corresponds with a specific ability that is granted to the tesseract while it maintains this shape. The available shapes are: shield, attack and lure.

    While in any form other than attack, the tesseract cannot make any physical attacks, including Opportunity Attacks.