Archmage Simulacrum

Simulacrum. When a simulacrum drops to 0 hit points or is subjected to a successful dispel magic spell (DC 17), it reverts to ice and snow and is destroyed. It is incapacitated while inside an antimagic field.

Repairable. As long as it has at least 1 hit point remaining, the simulacrum regains 1 hit point when a mending spell is cast on it.

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

Arcane Burst. Melee or Ranged Spell Attack: +8 to hit, reach 5 ft. or range 120 ft., one target. Hit: 22 (4d10) force damage.

Spellcasting (Recharge 6). The simulacrum casts one of the following spells, using Intelligence as the spellcasting ability (spell save DC 17):

at will: minor illusion, wither and bloom, comprehend languages, detect magic, floating disk, identify, illusory script, unseen servant, gentle repose, skywrite, feign death, phantom steed, contact other plane, telepathic bond, mending, prestidigitation

3/day each: alarm, tiny hut

1/day each: augury, find familiar, magic mouth, water breathing, instant summons, divination

Shield. When the simulacrum is hit by an attack, it calls forth an invisible barrier of magical force that protects it. Until the start of its next turn, the simulacrum has a +5 bonus to AC, including against the triggering attack.