The man running the popular @IraqSurveys Twitter account, an Iraqi living in London, usually collects legit information about the doings of ISIS and the forces fighting against them ... until he "got bored" and decided to start making shit up for the heck of it. He says that the name of the town should have tipped people off, since "shichwa" is an Iraqi Arabic word meaning "cheese bladder" (not to be confused with the city of Mozzarella Urethra, Delaware). Soon, people who did get the joke started adding more "information" about the battle, even making maps of the action going on in the nonexistent town.
"As you can see, the name is derived from the fact that city has the unmistakable shape of a cheese bladder."
The hoax's mastermind decided to come clean when he noticed that people on either side of the conflict were getting a little carried away, with anti-ISIS fighters bragging about their victory and pro-ISIS forces planning acts of revenge. Had the guy not admitted that it was all made up, this fake battle could have led to a very real one, becoming the second-biggest debacle ever started because of Twitter (after that time Miley Cyrus tweeted half a nipple).