What's the weirdest shit you've ever had to fight Veeky Forums?

I would post the picture of the T-Rex with Jeff Goldblum's face on it, but I can't find it.

A fifty-foot squirrel which nearly killed the party. It shot lightning from its mouth

...

Your magical realm called and has advised that you seek a therapist.

There was another where they fought giant grotesque babies piloted by intelligent regular-sized babies.

Basically, I would improvise scenarios based on a few idea generators and tables. The players were sent to different dimensions to do the dirty work of a vastly powerful wizard.