Dread Strike

You infuse your next melee weapon attack with necrotic power! Make a melee weapon attack. On a hit, a target suffer the normal weapon damage dice(s) plus 2d8 Necrotic damage. If a creature is slain by this spell, it will transform into a Ghoul at the start of the next round. This Ghoul is quickly wasting and will only last for a total of one minute before falling apart. While active, the Ghoul will attack the same target as the one who slew it at the end of the slayer`s turn. The slayer may use his/her bonus action to verbally command the Ghoul, which will follow the command to the best of its ability.  

At higher level. Increases the damage taken by 1d8 for each spell slot used above 2nd level.