Alchemic gas

You summon a cloud of greenish gas that fills a 6ft sphere and goes around croners it deal 2d8 poison dmg to ctreatues when they move into it or start their turn in it. The gas is reactive to fire and cold dmg When the gas is exsposed to fire or cold dmg it explodes in a 8raduis dealing the corasponding dmg type and forces creatures got in it to make a con save with a dc of 10 + your int or be ignited or frozen.