Did you ever think you could catch a trout with a mouse trap?
You've got to hand it to folks who know how to get around the backwoods.
He creates a particular form of triggered ice fishing set line, a quick-action method of using a fishing line, a baited hook, and a spring-powered trap to execute the hook set.
While you're watching this, ask yourself: Could I pull this off? Could I have even thought of this?!
Now, Greg is a legit bushcraft specialist, but he may have taken a few liberties with this contraption. We'll give credit where it's due, and acknowledge that it takes a certain type of mind to even come up with an idea like this. It's ingenuity at its best, and it's a quality that all bushcrafters need to develop.
When the going gets tough and you need to improvise, this is the mentality that's going to come in most handy.
All you really need is some relatively inexpensive fishing line, some stronger line to tie to the trap (Greg used the inner strands of some paracord), a flat board, a mouse trap, and a way to make a hole in the ice.