A: Wet feet.
Hop suey!
Because he crosses everything.
A. He can throw a set into the middle of a pond and not hit any of the ducks.
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 they couldn't cross the streams.
your boat, gently down the stream...