I don't have a hippo

Grandpa: And I created an alcoholic hippo. Homer: You never showed it to me! Grandpa: A stupid alcoholic hippo. Homer: I still wanna see it. Grandpa: There is no hippo! Homer: Then why did you say it? Grandpa: Cause you're the hippo! Homer: Are you just saying that 'cause you don't want me to see the hippo? Grandpa: I don't have a hippo!