How Dangerous is a Supersonic Nerf Dart?

I Built a Transparent Boomerang (it's lethal)

I Built an Extremely Powerful Slingshot

I Built a Transparent Katana

I Built a Whip that Crushes Bones

Holding Breath for 4 Minutes to Beat a Fear

Cracking Any Lock from $1 to $500

I learned to Fall Asleep in 2 Minutes

YESGO! Music I use (Free Trial): http://share.epidemicsound.com/MikeShake.