Polymorph Blade

Generic Variant, very rare (requires attunement)

When you attack a creature with this magic weapon and roll a 20 on the attack roll, the creature must make a DC 15 Wisdom saving throw in addition to suffering the attack’s normal effects. On a failed save, the creature also suffers the effects of a polymorph spell. Roll a d20 and consult the following table to determine the form the target creature is transformed into.

A creature is immune to this effect if it is immune to damage of the weapon’s type, is a shapechanger, or has legendary actions.

Curse

This weapon is cursed, and becoming attuned to it extends the curse to you. Until the curse is broken with a remove curse spell or similar magic, you are unwilling to part with the weapon. Whenever you attack a creature with this weapon and roll a 1 on the attack roll, you suffer the effect of a polymorph spell for 1 hour, rolling on the table to determine your new form.

Variants:

Polymorph Blade Longsword

  • Damage:
    • One-handed: 1d8 S
    • Two-handed: 1d10 S
  • Weight: 3.0 lbs.

Polymorph Blade Double-Bladed Scimitar

  • Damage: 2d4 S
  • Weight: 6.0 lbs.

Polymorph Blade Greatsword

  • Damage: 2d6 S
  • Weight: 6.0 lbs.

Polymorph Blade Rapier

  • Damage: 1d8 P
  • Weight: 2.0 lbs.

Polymorph Blade Shortsword

  • Damage: 1d6 P
  • Weight: 2.0 lbs.

Polymorph Blade Scimitar

  • Damage: 1d6 S
  • Weight: 3.0 lbs.

Source: Lost Laboratory of Kwalish p. 56