Fort My Kids

I caught a glimpse of this backyard construction my kids have been building lately and something in my brain banged and yelled urgently, waking me up from my March funk: What is wrong with this picture? I approached cautiously.
I'm reminded of one of those seek 'n find drawings.

I see a broken tailbone with a good knot on the back of the skull thrown in.

Do you have any idea how many times I've been to the hospital in the last few years?

I don't either but I've come to know a recipe for disaster when I see one.

This tree fell over in the heavy snow we had this winter. Now it's a makeshift climbing course/fort-holder-upper.

Sean, with excitement: I climb all the way out here and then bang through the branches until I hit the ground! Upon closer inspection....

I find boards with nails flung around the main floor of the fort.
Intentional obstacle course or wrecklessness?
I order Oldest to promptly find his brain, take it out into the backyard and quickly apply it to the matter at hand before the children come home from school. And also this foot-puncturing mother of all beds of upright rusty nails as well, please.
Don't even enlarge this photo, it'll make your toes curl.
~sigh~

Why.

What the.

This is the little house oldest boy built as an assignment for homeschooling many years ago.

I tried, people.

update: Right after I drew up a waiver for all the neighborhood parents to sign I noticed that Dad is out back fixing the contraption, muttering to himself about such things as the importance of nonhalfassedness. No need to call the authorities, a little public exposure and my reporting skills saved the children.