Deep Purifier's Eldritch Strike

Invoking the Deep Purifier, you create a claw made of spectral energy within range. Make a melee spell attack with the claw, reaching 5 feet away with it and with a +5 attack roll bonus. On a hit, the target takes 15d8 Force damage, and has a spectral gash if it doesn’t already have one. With a gash, the target takes 1d6 Force damage every turn for 1 minute, or until it receives magical healing. on a successful save, the target takes the normal damage but does not have the wound. If cast with a level 9 spell slot, the wound lasts for 2 minutes, and deals 2d8 damage instead of 1d6.