Wall of Spider Web, It's ON FIRE.

A blast of web comes forth from your hand and tries to restrain each creature in a 35ft by 35ft square. Each character must succeed a dc 13 arcrobatics or athletics. if the character fails they are considered restrained. After a round the web self lights itself on fire, each character on or restrainded by the webs takes 8d8 fire damage.

At the begingging of the round a creature that is on the web, they take 2d8 fire damage.

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the damage increases by 3d8 for each slot level above 5th.