Zach Hadel (/ˈheɪdəl/ HAY-dəl;[4]), known by his pseudonym psychicpebbles, is an American YouTuber, animator, writer, director, and voice actor.

[8] His short-form independent cartoons became popular online, such as his animated video responding to overuse of the "arrow in the knee" meme from The Elder Scrolls V: Skyrim which went viral in 2011.

[13] Hadel was a member of the YouTube group SleepyCabin and co-hosted SleepyCast, a comedy and discussion podcast hosted by former Newgrounds animators that launched on August 30, 2014.

[15] Hadel and Roiland also appeared alongside animator Alex Hirsch on h3h3's livestream podcast for charity[16] where they raised over $100,000 for California wildlife relief.

[17] Hadel hosted the podcast Schmucks from 2017 to 2019, where he interviewed fellow entertainers such as Michael Stevens, Finn Wolfhard, Jon Jafari, and Ethan Klein.