Ultimate Epic Battle Simulator is free to keep for a limited time on Steam.
From the description on Steam:
Here is a sandbox like no other. Create massive battles with absolutely no limits. Want to see 10,000 chickens fight an army of Romans?? Sure, why not. Want to see a company of WW2 U.S soldiers fight 11,000 Medieval soldiers?? There are simply no limits to the carnage you can achieve in UEBS.
haha awesome find!