Jimmy was killed a day after his 16th birthday
A bakery was left looking like a horror scene when a schoolboy was attacked and killed, the Old Bailey has heard.
Jimmy Mizen, 16, bled heavily when he was hit by a glass dish which severed vessels in his neck, in the bakery in Lee, south east London, in May.
Jake Fahri, 19, denies a charge of murder, claiming he acted in self-defence during an argument.
But Fahri was "smirking" as he ran away from the shop, having grabbed "any and every" weapon around, it was alleged.
Crispin Aylett, the prosecution QC, said Fahri became angry when Jimmy would not move out of his way in the Three Cooks Bakery.
"The defendant then grabbed a glass Pyrex-type dish from the counter and threw it at Jimmy. The dish hit Jimmy on the jaw," he said.
"It broke on impact."
"One of the staff at the bakery has described it as being like a horror film," Mr Aylett added.
The trial, which began on Friday and is expected to last three weeks, continues.