Burning Bog

You choose four (5 foot by 5 foot) squares anywhere within 60 feet of you, which become swamp-like pit traps that are 15 feet deep. Any creature that enters this area must make a Dexterity Saving Throw.

On a success, they do not fall in the trap and safetly return to an area of their choice within 5 feet of the pit.

On a fail, they fall into the 15 foot deep trap, dousing them in a caustic, highly flammable layer of dead plant life and they take 2d10 Acid damage and are now flammable for the duration. If they are hit by fire damage within the duration (unless the spell states it does not light things afire) they take an additional 2d6 fire damage.

When the spell ends, the pits are sealed and all doused targets are dried.