The Xbox 360 team in Mexico City felt the pressure to compete with the big piñata party in Los Angeles, and decided to build a record-breakingly large Horstachio. However big you're imagining, this thing is bigger.
The project was undertaken at Six Flags Mexico and resulted in a piñata that was 48 feet tall, and weighed in at 4,400 pounds. The construction and detailing involved over 800 people, including the children of Microsoft employees. I can picture it now: "Little Diego, get this harness on. Daddy really needs your help with Horstachio's right ear. Be a brave little boy."
Guinness has yet to certify the piñata as the world's largest, but i can't imagine they'll have any trouble once the fact checkers get out to Mexico City. A giant Horstachio is cool, and all, but fill that sucker with Kit Kats, and I'll be on a plane tomorrow.
Here is a photo from gamerscoreblog: