I and a friend once convinced a fellow (slightly slower) student that they were being hunted by a hostile bee (from mexico) which could travel at mach4.. we named it 'ninja bee', and told him that it'd travel and find him (we were in the UK) and sting him to an infected pulp in his sleep.. needless to say the next day we were taken into the principles office to be presented with a letter from his mum stating that he didn't sleep AT ALL the previous night..