Fizban's Treasury of Dragons, pg. 19

Ashardalon’s Stride

3-level Transmutation

The billowing flames of a dragon blast from your feet, granting you explosive speed. For the duration, your speed increases by 20 feet and moving doesn’t provoke opportunity attacks.   When you move within 5 feet of a creature or an object that isn’t being worn or carried, it takes 1d6 fire damage from your trail of heat. A creature or object can take this damage only once during a turn.
At higher levels: When you cast this spell using a spell slot of 4th level or higher, increase your speed by 5 feet for each spell slot level above 3rd. The spell deals an additional 1d6 fire damage for each slot level above 3rd.