Peter Harvey denies a charge of attempted murder in July 2009
A pupil who was attacked by a Nottinghamshire teacher was regularly in trouble for disrupting lessons, Nottingham Crown Court has heard.
Peter Harvey, 50, denies the attempted murder of a boy at All Saints' Roman Catholic School, Mansfield, while trying to restore class discipline.
The 14-year-old, who said he could not recall the attack, denied being a trouble-maker.
He was left with a fractured skull after being hit with a dumbbell.
Rex Tedd QC, defending, said the victim regularly disrupted lessons and was a "leading light" in classroom trouble.
Taking the stand, the boy denied accusations he had disrupted lessons nine times in the year before the attack.
A classmate admitted pupils would secretly film teachers as others tried to "wind them up". The footage was then shown around the school because it was "funny".
Students were filmed calling Mr Harvey a "psycho" in the moments leading up to the attack.
The court previously heard Mr Harvey dragged the boy into another room and beat him with the 3kg (6.6lb) dumbbell while shouting, "Die, die, die", in July 2009.
Mr Harvey denies attempted murder and causing grievous bodily harm with intent, but has admitted a charge of causing grievous bodily harm.
Class was 'rowdy'
The court was shown a recorded police interview with the victim, in which he described the moments before the attack.
The boy swore at the teacher after being disciplined for waving a wooden ruler and a Bunsen burner about, the court heard.
He told police the last thing he remembered was being dragged from the classroom.
He added: "I can remember all the class being noisy and rowdy.
"He said something to me and I swore at him. He said, 'I'll teach you' and swore at me.
"I can remember being dragged out of the classroom and into the corridor."
Another boy, now aged 15, who witnessed the attack, told police Mr Harvey acted "as if possessed" when he grabbed the victim.
The witness said: "He was unusually scary, it wasn't normal.
"It was like something had possessed him, you could see he wanted to kill him, sort of thing.
"He was so angry it was like he had an extra power to do it."
Recalling the attack with the dumbbell, the witness added: "He was just striking him with it and was just saying 'Die, die, die'.
"Blood was pouring out of his face.
"His eyes were open and I thought he was dead.
"He [Mr Harvey] came out looking calm, like he hadn't done anything. A teacher had his arm around him."
The trial continues.