The penguin court

I come before the penguin court,
They’re kind of meaner than I thought.
They glare upon me once again
With flappy feet and fishy brains.
One slides towards me on his belly,
And leads me to a giant jelly.
It’s slimy and it’s green, of course
(The penguin leader’s voice is hoarse).
My sentence is to step inside,
You can’t run but you can hide.