To my great surprise, I actually took the time to finish Enough Plumbers over the weekend.
This is the beginning of the final level.
Yes, the beginning. When you try to talk to the princess, either she is captured by or turns into this.
If you can't see him very well, here's a closer look at him:
He's also a puzzle boss, which is to be expected. I'm curious, though-who is that supposed to be?
The congratulations screen is pretty funny, too.
Not much else to say about it...