The Chief Executive Officer of a (bad) video game company called "Leek Cartridge", Pop transforms into the grey bunny Seratonin using the "digital clock wind" wristband. When she transforms, she says "Come out, Seratonin!" and can call wild birds with a whistle. She is the dark-skinned girl who always wears hats. She is usually the one who comes up with the plan to defeat the monsters. Seratonin is the chemical in the brain which causes happiness.
-bio taken from Wikipedia