Increase the blood temperature to a boiling point
Create a fist and direct at target
Blood Boiling is the ability to increase blood temperature to a boiling point. Victims of this power are subjected to intense pain, heatwaves and have difficulty breathing until they are eventually killed.
The warlock Nicholas was the only known being to possess this ability. He was strong enough that he didn't have to be touching his victims in order to boil them. He nearly killed Patty Halliwell with this power before forcing her to bless his ruby red ring and give him immunity to the Charmed Ones' powers.
His ring greatly amplified his power, allowing him to boil multiple people at once. When the Charmed Ones came into their powers 23 years later, Nicholas nearly killed them before Phoebe used her last ounce of strength to cut his legs out from under him.
A half year after he was vanquished, Nicholas was resurrected by Abraxas, who then sent him after Prue. Overloading her brain from the boiling, Prue managed to vanquish him again before she collapsed.