Train Lightning

To cast this spell, the spellcaster must speak the phrase: "I like trains".

A Train made of lightning forming a track 40 feet long and 5 feet wide blasts out from a point you can see within 30ft in a direction you choose. Each creature in the line must make a Dexterity saving throw. A creature takes 8d6 lightning damage on a failed save, or half as much damage on a successful one.
The train lightning ignites flammable objects in the area that aren't being worn or carried.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d6 for each slot level above 3rd.