The Moletank, Mr. Bamt, was briefly introduced as a General to take over Tankorr's duties.  It didn't work out so well.  Well, Read the FAQ if you want to know why...

His Robot mode is... Interesting.  He goes whiz when he moves, and pop when he stops, and whirr when he stands still.  I've never known just what he was, and I guess I never will.