PROTIP: Check your volume, screaming.
This is a video of magician Rahat Hussein (of the invisible driver drive-thru prank fame) trying to scare people with an alien chestbursting prank. It's decent. Plus you can buy the costume for $30 to do it yourself on Halloween HERE. Although, personally, I don't think I'd be scared. I'd be like the guy at 0:45 who just smiles and keeps walking. I live in a bad part of town, I'm used to people running up to me screaming. Granted I've never witnessed an alien burst out of their chest, but that actually ranks pretty low on the extremity of things I've seen. I once had some crazy guy come running up to me WITH HIS PENIS IN HIS HAND. It was not attached!
Keep going for the video.
Thanks to Duncan, who would have torn that thing out of his chest and stomped it.