Unearthed Pestilence

You summon a malign plague from the hereafter and bind it into a piece of ammunition, imbuing the projectile with foul, suppurative energy.

A creature hit with an attack using this projectile takes 2d8 necrotic and 2d8 poison damage, in addition to the attack's normal effects.

Until the spell ends, the ground in a 20ft radius centred on the point where the projectile landed becomes suffused with thick black spores, moving with the target if the attack was successful. This area is difficult terrain, and a creature that ends its turn in the radius must succeed on a Constitution saving throw or become poisoned for 1 minute.

Hit or miss, once the projectile lands it crumbles away into ash.

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the necrotic and poison damage each increase by 1d8 for each slot level above 4th.