Other mistake: At the beginning, when everyone is watching Shelby fighting on TV, the timer is going too slow. According to the timer, the fight ends at 2:53, which is only 7 seconds of fighting, yet the fight was way longer than that.
Other mistake: When the military barge into Nevel's house, Uncle Roger puts the camera down and you can see it not moving whatsoever, but in the shot from the POV of the unmoving camera the shot is moving.
IWanna Stay with Spencer - S1-E5
Other mistake: The "Fan of Hammers" has all the hammers pointed the same way. But when the hammer goes into the wall, it goes in backwards. It is also there through all the rest of the shows and even in season two, where in "iKiss" it has a black handle. (00:02:35)
Other mistake: There is an A stuck to Carly's butt, but nothing touched Carly's butt when she got downstairs. (00:20:30)
Other mistake: In the theme song opening of iCarly, The Slap is saved under their favorites on their computer. The Slap is Hollywood Arts' website. Why would people living in Seattle go on a school website for a school in Hollywood?
Other mistake: When Carly and Sam are pumping the watermelon full of air, one shot zooms in on Carly's finger as she hits the on-switch. The device is turned off as she removes her finger. (00:01:32)
Answer: In direction translation it means 'Mischievous Spirit'. 'Hob' as in HobGoblin means clown or prankster, and 'Knocker' was an old age term for Poltergeists in mines. Miners would often complain of hearing knocking sounds down mines when there was no-one else down there, hence 'Knocker'. It's not a regular English expression though.
GalahadFairlight