El Ruido is a psychotic gremlin whose only goal in life is to make Madeo's life a living hell. He dons a red onesie featuring a yellow inverted heart symbol at its center, along with white gloves and a quirky taco hat. His unique appearance is further accentuated by his yellow and red antennas, with the right one ending in a crooked shape. He exhibits a highly frenzied and unstable personality, often communicating in a blend of English and Spanish, though mostly yelling in Spanish when he's mad.