Self-Destruct. The mineshaft collapses in on itself, killing itself and anything within 100 feet of it, including the interior. It resurrects in 1d10 days.

Spellcasting. The mineshaft is a 60-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 27, +14 to hit with spell attacks). The mineshaft has the following spells prepared:

Cantrips (at will): Light, Lightning Lure, Mind Sliver, Sword Burst, Thaumaturgy, Vicious Mockery, Word of Radiance

1st level (12 slots): Cause Fear, Command, Compelled Duel, Dissonant Whispers, Distort Value, Ensnaring Strike, Faerie Fire, Feather Fall, Hail of Thorns, Healing Word, Hunter's Mark, Searing Smite, Silvery Barb, Thunderous Smite, Wrathful Smite, Zephyr Strike

2nd level (9 slots): Blindness/Deafness, Blur, Branding Smite, Darkness, Earthbind, Knock, Misty Step, Prayer of Healing, Suggestion, Tasha's Mind Whip, Warding Wind

3rd level (9 slots): Aura of Vitality, Blinding Smite, Crusader's Mantle, Fast Friends, Intellect Fortress, Mass Healing Word, Motivational Speech, Thunder Step, Tongues

4th level (9 slots): Aura of Life, Aura of Purity, Dimension Door, Guardian of Faith, Guardian of Nature, Raulothim's Psychic Lance, Staggering Smite

5th level (9 slots): Banishing Smite, Circle of Power, Contact other Plane, Destructive Wave, Far Step, Geas, Immolation, Negative Energy Flood, Teleportation Circle

6th level (6 slots): Mass Suggestion, Otto's Irresistible Dance, Scatter, Word of Recall

7th level (6 slots): Divine Word, Power Word Pain, Teleport, Whirlwind

8th level (3 slots): Glibness, Maddening Darkness, Power Word Stun

9th level (3 slots): Power Word Kill, Time Stop, Wish

Banish (3/day). The mineshaft casts banishment on up to 2 creatures. The banishment lasts until the creature succeeds on their saving throw.

Imprison (3/day). The mineshaft teleports one creature that is inside of it to one of the mineshaft's prison chambers. The creature is bounded with chains during the teleportation, which requires a DC 27 Strength check to break out of, and a DC 23 Thieves' Tools, or a DC 27 Dexterity check to open the cell door.

Multi-attack. The mineshaft makes 1 stalactite attack, 1 stalagmite attack, and 2 spell attacks.

Stalactite. Melee Weapon Attack: DC 27 Dexterity Saving Throw, a 5-foot sphere within the mineshaft. Hit: 23 (3d10 + 7) bludgeoning damage and 12 (2d8+3) piercing damage.

Stalagmite. Melee Weapon Attack: DC 28 Dexterity Saving Throw, a 5-foot sphere within the mineshaft. Hit: 37 (6d8 + 12) slashing damage.