Cira's Pillars of Venom

You conjure forth columns of toxic gas to choke away those that dare oppose you.

Target 4 points within range, Large pillars of caustic green smoke appear at the chosen points and begin spewing poison into the surrounding area and last until the spell ends. Each creature that starts their turn within 30 feet of a pillar must succeed a constitution saving throw or  be poisoned for 1 minute.

While a creature is Poisoned this way its movement speed is halved, it has vulnerability to Poison damage, and takes 4d10 poison damage at the beginning of it's turns.

When Cast at higher levels the duration of the spell increases by 10 minutes for each slot level above 6th.