Network Spoofer didn't last long in the Google Play Store, but that's one of the great things about Android; Google can't stop the signal. Network Spoofer still exists on Source Forge, and is supported on a number of devices. Root is required for this one, and that's not surprising - it allows you to mess with your friends by redirecting all network traffic via your device.
You can send every web page to a specific site, flip all images, or just pass all network traffic through your phone so you can... have a look. Obviously, this app has malicious potential, so be good, folks. There is also a hefty 99MB download associated with the app.