Karl Leslie Fink is a recurring character of Disney Channel's Original Series, Dog With a Blog. He is Avery's nemesis, as they compete as the two smartest kids in school. At Little Smarty Science Camp, Avery stole his graham crackers, which Karl hates her for. He often has tea with Ellen, his obvious crush and he sends her flowers very often under the name "Walter Perkins". He is mean, and is considered a jerk by Avery and Stan. He is also nosy, as he was obsessed with trying to figure out Stan's secret after he heard Avery and Chloe talking about him. Eventually, he does discover it but has vowed not to tell anyone (including his mother) after Avery sent his mother a text about the actions he was doing spying on Stan and nearly getting them both in trouble.