"This Yo-kai sneakily opens all of your zippers. And before you know it, they're all open! Open zippers are really troublesome, both for backpacks and pants."
Yo-kai Medallium biography
"This Yo-kai unfastens zippers when you're not looking! That's never going to end well..."
This Yo-kai first appeared in EP116, where he unzipped Nate‘s fly several times, embarrassing him and others. Nate being embarrassed and screaming caused the door to the High-Fright Zone open up all the way. At the end of the school day, Whisper introduces the backpack Yo-kai formally. Nate was already angry and hit the backpack Yo-kai with his paper fan, sending him flying.
Etymology[]
"Zip Unlock" is a portmanteau of ziplock and unlock.
"Cremallero" is a corruption of "Cremallera" (Zipper).
"Cernyer" is a corruption of "cerniera" (ziplock).