Here is a spell that Warlocks might like!
Casting Time: 1 action
Range: 100 feet
Components: V, S
You choose a target in range and a willing ally in range. The willing ally only gets to choose at start of the spell to be willing and is at your mercy for the rest of the spell. You deal both targets 10 damage. This damage may not be prevented or reduced by any means. The target may choose to take an additional 10 damage that may not be prevented or reduced by any means to deal an addition 10 damage to your willing ally. If the target chooses to do this, then you may choose to deal an additional 10 damage to both targets that may not be reduced or prevented. If you choose to do a second volley of damage to the target and ally, the target may then choose to do a final 10 damage to both targets. The willing ally and the target must have enough hit points for the damage to fully take effect for either you or the target of the spell to choose to do damage. The damage must always be dealt to the same willing ally.
At Higher Levels: When you cast this spell using a higher-level spell slots, you and the target may choose to do an additional round of damage for each spell slot above 2nd.