Hellish rebuke

Hellish rebuke is a basic spell known to all warlocks of the infernal pact. When cast, hellish rebuke causes a creature of the warlock's choosing within fifty feet of him or her to burst into flames channeled straight from the Nine Hells by the warlock's pain and rage. The intensity of the flames is, for the most part, determined by the capacity of the warlock themselves to take damage, and with more experience the spell grows in power substantially. As the most basic of all spells used by warlocks in the service of devils, hellish rebuke can be cast as many times per day as the warlock wishes.