Crystal Magic Weapon

You touch a mundane or magic weapon. Until the spell ends, the weapon is encrusted with jagged blue crystals. The weapon deals an extra 1d8 Force damage to any creature it hits.

Additionally, the first time the wielder hits a creature on their turn, the target’s AC is reduced by 1 until the start of the wielder's next turn, as the crystal buildup creates structural weak points in their armor or hide.

At Higher Levels: When you cast this spell using a spell slot of 5th level or higher, the extra damage increases to 2d8. When you use a slot of 7th level or higher, it increases to 3d8.