Mentiras Con Patas / Lies with Legs - Kumanakris - Bog

"Akira and Naoko are tired of Hiro telling one lie after another. In order to get his brother to be truthful once and for all, they decide to cast A TRUTH SPELL on him! But the spell has unexpected side effects: every time Hiro tells a lie, a little monster magically appears . . . until the brothers are surrounded by little monsters!"--Amazon.