What's a casual way to start a video? How about a fun little opening introducing what you're going to do or make. You could say something like, "Arrows are normally a good way to pierce a skull, but I'm concerned that [they] may not destroy enough brain matter." Light hearted fun!
Of course over at the Slingshot Channel Joerg develops weapons to protect himself and others from zombie invasions, so he's thinking about how best to target zombie brains here. The Slingshot Channel is apparently working on a zombie movie, so weapon and ammo production is going to kick into high gear, and maximum destruction arrowheads are a perfect jumping off point. No broadheads or bodkins here.
Joerg uses scrap iron and steel angles so the arrow pierces the skull at a narrow point, but then sharp metal blades swing around and begin hacking at any zombie gray matter in their path. If you were scared to cross Joerg before, you should definitely hope now that you don't catch him on a trigger happy day.