Atlantis14

You sit there and wait for hours. You try to pass the time by counting the plants on the wall, when you suddenly realize that it isn't a wall at all! It's a very, very, dirty, muddy person! Suddenly, he speaks. "Welcome to Atlantis, newcomer. I have affected your will to make you stay here. That is because you are a land dweller, and land dwellers only enter if they can answer my riddle." "Hear my riddle now: A man who walks with many legs, yet only none at all. This man, no man is he, you see, is a man as tall?" 
What do you answer?
yes
no
I refuse to answer that riddle!