Knock, knock! Who's there? Hippo. Hippo who? Hippo birthday to you, hippo birthday to you.
Knock, knock!Who's there?Hippo.Hippo who?Hippo birthday to you, hippo birthday to you. 0 0 0 Knock-knock jokes
Knock, knock!
Who's there?
Hippo.
Hippo who?
Hippo birthday to you, hippo birthday to you.