Plus 4 Heads?

Riddle: 20 people dove into a pool. Nobody was already in. There were no animals. Nobody went in, and nobody came out. when they all came out, there were "24 heads". How can that be?

Answer: There were 20 FORE heads!

Source: https://www.riddles.com/8193

20 people dove into a pool. Nobody was already in. There were no animals. Nobody went in, and nobody came out. when they all came out, there were "24 heads". How can that be? — Plus 4 Heads? by pusheen5555 Riddle