A person that is thinking many different almost unconnected things and usually tells them aloud without consent; one with a vast of random thoughts
Lucy: What is with Tom today? He won't shut up. And barely makes any sense
Tom: Oh man. The Red Hot Chili Peppers are performing today! Speaking about chilies, I could go for some Mexican food about now. Yeah! What is Obama going to do about immigrants....
Josh: Seriously, what a Polka Dot Head!