Stupid question

ok, i'm new, but i have a question. In a couple of my games I have come across someone having their armies multiplied for the next couple of rounds. How does this happen?
Thanks for the help
Thanks for the help
Conquer Club, a free online multiplayer variation of a popular world domination board game.
http://www.tools.conquerclub.com/forum/
http://www.tools.conquerclub.com/forum/viewtopic.php?f=6&t=17193