Is there any formal name for this type of trap?

it's commonly called a spiked whip trap, commonly used in Vietnam due to it's simplicity. here's a website reference:

http://www.5rar.asn.au/weapons/boobytraps.htm (a little more then half way down)

as for it being illegal to make literature about this stuff, FALSE! it's history and is legal to publish as long as it's in good faith and not meant to teach people to use them against other's and pose danger to others, then a DHLS will be knocking on your door.

It's named the "pig stabber"

because (yes, it can be used for anti-personnel) it's set with a simple trip line over a game trail and is capable of inflicting the necessary damage to kill hogs.

Books can't legally teach the construction of snares like this anymore, so if you're lucky enough to get your hands on a "bushcraft" or similar survivalist guide pre-80's then you might find some snares like this.

@storm, yes, checking the link that you posted, you are correct, IT GIVES A DESCRIPTION, not instruction on constructing devices because it cannot legally be published in text... I'm sure you can find it online somewhere

and I'm guessing that you would say the same about C4 since it is historical, correct? no, the "anarchist" handbooks that gave instructions on bomb making were made illegal and any text that was meant to be more than a description cannot legally be published

ps- thanks for the negative rating

It's called a snare