VIDEO: Watch RTÉ staff get pranked with a giant megaphone

(But don't mess with Rick O'Shea)

You know the office prankster - that loveable scamp you want to kill, but at the same time, acknowledge he's great craic?

Enter Carl Mullan, creeping up behind unsuspecting presenters and office staff to scare the living daylights out of them. Screams aplenty.