A dead centipede.
Someone who lies awake at night if there really is a dog.
Disclaimer: I don't know how well this joke will work in English. What's yellow and lies in a pond? An excevator. You don't think this is funny? Neither does the operator.
Because if it was 12 inches it would be a foot!
Potato!
When you swerve to miss a tree and realize it was your air freshener
A baseball is thrown to the air.