Corrosive Spit Eldritch Blast

You hurl a beam of poisonous energy. Make a ranged spell attack against one creature or object in range. On a hit, the target takes 1d10 Acid damage.

Effect: On hit, the target takes 1 ongoing acid damage at the start of its turns until it uses an action to scrape the acid off or succeeds on a Con save at the end of its turn (save DC = your spell save DC). Ongoing damage equals 1 at 1st level, increases to 2 at 5th level and 3 at 11th level.

Cantrip Upgrade. The spell creates two beams at level 5, three beams at level 11, and four beams at level 17. You can direct the beams at the same target or at different ones. Make a separate attack roll for each beam.