Egg Monsters From Mars (Goosebumps)

When Dana Johnson has to take part in an egg hunt for his little sister Brandy's birthday, he's not very keen. He'd rather be studying insects through his microscope. But then he finds The Egg. It's not like a normal egg though. It's huge, it's covered with veins and it's warm. Where on earth could it have come from? And exactly what is going to happen when it hatches?