Waterspouts are simply tornadoes that exist over a body of water. They are often much weaker than land-based twisters due to atmospheric differences.
Waterspouts are able to pick up the water and swirl it in its funnel. In some occasions, waterspouts have picked up tadpoles, lizards and fish which eventually rained down from the sky once the waterspout diminished.
These forces of nature often occur in tropical regions where there are oceans and lakes but can also occur in less tropical areas such as the Great Lakes. Ships out on the open seas have reported seeing up to as many as 30 waterspouts in one day!