Helga's Boyfriend / Crush on Teacher - S2-E14
Other mistake: Helga's Boyfriend: At the Stake Time roller rink, when Helga and Stinky are spinning around like a tornado, many of the kids are standing in mid-air. Brainy and Park are also standing in mid-air in an earlier shot where Helga tells Stinky, "Let's go!" (00:03:58)