20 best on-set practical jokes

The neutron cream

The Prank: In what is one of the highest-profile on-set pranks of all time, Simon Pegg tricked co-stars Chris Pine, Zachary Quinto, Zoe Saldana, John Cho, Karl Urban and Benedict Cumberbatch into applying a completely made-up 'neutron cream' for health and safety reasons and to jump up and down to "help with the ions".

The best reaction Pegg got was from Cumberbatch, who signed a form relating to the cream and later read the form out loud and to camera, discovering only then that "neutron cream does not exist" and that "jumping up and down and shaking my hands makes me look like a silly bastard".