Green-Flame Blade

You brandish the weapon used in the spell's casting and make a melee attack with it against one creature within 5 feet of you. On a hit, the target suffers the weapon attack's normal effects, and you can cause green fire to leap from the target to a different creature of your choice that you can see within 5 feet of it. The second creature takes fire damage equal to your spellcasting ability modifier.

Cantrip Upgrade. This spell's damage to secondary creature increases by 1d8 when you reach 5th level (1d8 + your spellcasting ability modifier), 11th level (2d8 + your spellcasting ability modifier) and 17th level (3d8 + your spellcasting ability modifier). This spell's damage on hit increases by 1d8 when you reach 11th level (2d8) and 17th level (3d8).