Boku no Mushi Kago

At school the protagonist is bullied, while at home he's forced to live with the gold-digger stepfamily of his absent father. He finds solace with his friends, which consist of pets such as reptiles and insects. One day he discovers that one of his bullies is afraid of a spider. Shortly after, he discovers he can make any girl obedient with his "power": a fearful obedience instilled by waving one of his uncute pets in her face. With the aid of a secret dungeon under his house and tons of bondage equipment, along with an aphrodisiac he developed from his friends' venoms and secretions, he begins to wield his power in an aggressive campaign of vengeance.