Acid Bite

You summon a spectral insect that latches onto a creature you can see within range. The target must succeed on a Constitution saving throw or take 1d6 acid damage. If the target is below half its hit point maximum, it takes an additional 1d6 acid damage.

Cantrip Upgrade.  Both damage dice increases by 1d6 when you reach levels 5 (2d6), 11 (3d6), and 17 (4d6).