Mindsaber

This item appears to be a metal rapier hilt with no crossguard. Instead of a blade, the hilt is set with a jagged purple opal crystal. You can use a bonus action to cause a blade of crackling psionic energy to coalesce, or disperse the blade. The blade emits purple dim light in a 10 foot radius, and attacks with the deep purple blade assaults your enemies' minds as much as their bodies.

You gain a +2 bonus to attack and damage rolls made with this magic weapon, which deals psychic damage instead of piercing damage. You also add the target's Intelligence modifier to the damage (minimum of 0), turning their own mind against themselves.