Undyne the Undying

Spears. Undynes Spears are all magically constructed from undynes determination, Much like the Spiritual Weapon spell. She can do this infinitley. The damage done by spears count as magic damage.

Innate Spellcasting. Her spell casting ability is charisma (DC 25, +10 to hit with spell attacks) and has the following spells prepared.

Cantrips (at will): Fire Bolt, Mage Hand, Shocking Grasp, Chill touch
1st level (6 slots): False Life, Magic Missle
2nd level (4 slots): Cloud of Daggers, Shadow Blade
3rd level (3 slots): Fear, Dispel Magic

Legendary Resistance (3/Day). If Undyne fails a saving throw, she can choose to succeed instead.

Reconstruct. At the beginning of every turn where she isnt at full health, she regains 1d20 hp.

Multiattack. Undyne makes 3 spear attacks, 2 melee and 1 thrown.

Spears. Melee or Ranged Magic Weapon Attack: +15 to hit, reach 5 ft. or range 20/120 ft., one target. Hit: 32 (4d12 + 6) piercing damage, or 44 (6d12 + 6) piercing damage if used with two hands to make a melee attack.

Parry. Undyne adds 10 to her AC against one melee attack that would hit her. To do so, she must see the attacker and be wielding a melee weapon.

Undyne 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. Undyne regains spent legendary actions at the start of her turn.

Attack from below. Undyne makes Spears shoot up from the ground, everyone needs to make a DC 23 Dex save or take 44 (6d12 + 6) piercing magic damage.