Bloody Ballista Cannon

You sacrifice a number of hp up to half your max hp. Your blood is transmuted into an ironbloodcrystal spike then accelerated to hypersonic speed towards  a target you can see within range. Make a ranged spell attack against the target. On a hit, the target takes 3d10 piercing damage. Hit or miss, the spike then explodes. The target and each creature within 10 feet of it must succeed on a Dexterity saving throw or take twice the amount of hp that was sacrificed in thundering damage.

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the piercing damage increases by 1d10 for each slot level above 4th. And the area of effect range of the spell is increased  by 5ft for each spell slot level above 5th.