Back in the 1980s I order a shipment of ladybug and preying mantis eggs for gardening purposes. The sender gave us a date for mailing and a date for delivery. We had a vacation planned between those dates.

They shipped early. They arrived early and were held by the post office. During the vacation hold, the eggs all hatched. The post office's storage area was filled with ladybugs and mantises. They were not pleased when we picked up our vacation mail. There were still a few hundred in the box, though.