What's a hermaclam?

Lately Aiden has been saying a lot of funny things. I keep blogging about them so I won't forget them. The other day he was playing Guitar Hero at his aunt's house. (Which he is actually pretty good for a four almost five year old) He played on the song "Rock me like a Hurricane" then afterwards he kept singing it, only he said, "Here I am, walkin' like a hermaclam."