3D Practice
From Screamer Wiki
"3D Practice" is a simple little prank published to Newgrounds in 2007. The video simply starts off by showing a series of 3D animations to catch the viewers' attention, but not long after that, a zombie will pop into the animation and shriek. Surprisingly, this flash was rated suitable for everyone, though this was most likely done to trap certain users. The original maker or where the flash is after getting deleted from the site is not known.