Fungi on the lawn

We have had the weirdest mushroom like things growing in our front yard. They appear out of nowhere, grow at superspeeds and then fall apart and die just as quickly as they come.

This is day 1. They were not there the night before.

This is day 2. By day 3 they had broken into pieces.

We've probably had about 20 of these grow in our yard in the last month or so. I am fascinated by them and freaked out at the same time.