Wisenberg is a student at Port Doover Elementary, who's managed to stay off the radar of Theo for a long time with his secretive and stealthy abilities. He's started his own secret society in the basement of the school, where he and two other nerds have created a super nerds club. He appeared in "The Gifted Class
Weisenberg is a tall boy with curly ginger hair
He may be a reference to Heisenberg, the alias of Walter White in Breaking Bad, since he wears a similar hat.