Level 8 warlock. Eldritch blast
You may choose to lose an eldritch blast charge for the rest of the level in order to revive a dead ally. They cannot have been dead for more than 3 days. If you do this, you may double your constitution modifier for your hit points until you level up again and get the charge back. You must recieve the charges back when you level up. You add your original con mod's worth each time you use this. So if you use it 3 times, then you quadruple your original amount.