Bus Full of Children vs Fish

This is a dark and morbid joke. The setup creates a disturbing image of a bus full of children, which makes the simple answer "The fish can swim" unexpectedly funny, since one is alive and one is not.

• Fish
• Bus
• Difference
• School
• Animal
• Death

• What's yellow and can't swim? A school bus full of children.
• What has 30 legs but can't swim? A bus full of children!
• What's the difference between meat and fish? If you beat your fish, it'll die.