Fairday's Riddle: Something's Afoot...

Hello, Riddlers! Can you guess the answer? Margo loves spotting them. ~F

My front door is my back; my foot's below my belly sack. I keep a slow, steady pace; I'm not going to win the race. I like it moist, soft, and warm. I goop around bugs and thorns. Garden greens are a treat. I may be slimy, but I'm surely neat! 

What am I? Stop by Sunday for the answer

I gave you a clue!

FEAR NOT THE UNEXPECTED