Patrick is the main antagonist of the Supernatural episode "The Curious Case of Dean Winchester". He is a 900-year-old Irish witch that gained immortality by gambling with the years of humans.
He was portrayed by Hal Ozsan.
It was Bobby who first encountered the witch and played against him in poker, originally losing 25 years to his age manipulation spell, which Patrick also used to prolong his life. This caused Dean to search Patrick out. Dean found Patrick in a bar talking to a wealthy man with a young woman on his arm. Dean pulled a gun and brought Patrick to the back room to play him. Dean lost, and they began to look for a way to reverse Patrick's spell.
So they followed him, and witnessed him steal a car. Later, Patrick caught them in his hotel room and told them it's not the chips doing the magic, but him. Dean tried to play him again, but Patrick refused. Instead, he asked Sam if he wanted to play. Sam refused, and as they were leaving, Patrick gave Sam "the Clap" (Gonorrhea). Sam later returned to play Patrick, and Patrick confronted Sam about cheating after the break. They continued playing when Patrick revealed Dean didn't have much time left. Sam beat him in poker and Dean returned to normal.
Patrick was later forced to play his girlfriend as she wished, and she lost.