Will Ferrell arrive at Step Brothers Premiere - held at Mann Village Theater, Westwood, California - 15.07.08

The Elf star suffered nightmares about becoming the size of an ant after a neighbourhood bully threatened to bring him down to size.

Ferrell recalls, "He threatened to put shrinking powder on me and I believed he had the ability to do that.

"He had some vial of something and said, 'This is shrinking powder. You better watch it!'

"Eventually my mom marched me over and told the kid to tell me it wasn't real."

Source: WENN