A carpet of fine sparkling particles falls and covers an area 20 feet square. A creature (your choice) in the area begins to glow with flames matching the color of the candle wax if it fails a Dexterity saving throw. While glowing, the creature takes 2d6 fire damage at the beginning of it's turn, and any attacks against it have advantage if the attacker can see it. The affected creature can't benefit from being invisible. It can make a Dexterity save at the end of its turn to end the effect. For the duration, creatures affected shed dim light in a 10-foot radius. 

When cast with a higher level spell slot, another creature may be affected per level higher. i.e. Witchfire cast with a level 4 spell slot can affect 3 creatures.