Ether-Flame-Run

Until the start of your next turn, the target's base movement speed is increased by 15 ft.

Until the start of your next turn, the target shifts to the border ethereal plane (as if by the spell etherealness) while it moves. A trail of blue fire appears behind the target, in the material plane, when they run. The target may attack like normal. Anybody who comes into contact with these flames must make a dexterity saving throw on a success the creature takes half damage, on a fail they take fire damage equal to 1d8 + your spellcasting modifier. The flames last for 1 minute after creation (the duration of the spell).

When cast at higher levels the damage this spell deals an additional 1d8 of damage for each level above 4th and increases your movement by an additional 5 ft for each level above 4th.

(this spell is meant to be cast on yourself but I made it ranged purely so you can cast it on your monk)