From the publisher:

"The card game of War with a Jurassic Twist!
Don't lay an egg!

The card game of war has never been so much fun! Larger dinosaurs defeat smaller dinosaurs, alike dinosaurs go to war, and dino eggs (if not eaten) hatch into new dinosaurs."

In this game, some cards depict eggs. When a player flips an egg card, then the egg will hatch by adding 2-4 cards (depending on the number of players) face down to the pool and then a face-up card which represents the new dinosaur hatched from the egg. Also, some dinosaurs are "egg-eaters", which when matched up against an egg card, will eat the egg card before it can hatch.