Booming Blade

Casting Time: 1 act./Range: 5 ft./Dur.: 1 round
As a part of the action used to case this spell, you
must make a melee attack with a weapon against
one creature within the spell's range, otherwise
the spell fails.
On a hit, the target suffers the attack's normal effects, and it becomes sheathed in
booming energy until the start of your next turn.
If the target willingly moves before then, it immediately takes 1d8 thunder damage, and the
spell ends.