Mystery Plant Plagues Property Owners

Update: It's thistle. Enormous, monstrous thistle.

I found about 6 of these plants on my property, and photos are from this morning.

The plants are 4 - 9 feet tall, growing in a wet prairie setting.

Of course, my first thought was "Oh no! Giant Hogweed!"

After some research, I'm not so sure.

It hasn't bloomed and finished developing, yet.
When compared to Giant Hogweed it seems these leaves are different, and the stems don't have those telling purple splotches.

What do you guys think?

And yes, I've already sent photos to the MDARD requesting identification help.

 

Harvested our first Kakai pumpkin (way, way early in the season).
Cat for scale.