Shortly before the biggish bang

George came home from a pal's birthday party with this balloon. 

After doing some helium-voices, he decided to try something he'd seen on YouTube: you hold a mobile phone against an inflated balloon, then slowly let the air out. The rubber is meant to wrap itself tightly against the phone to form a cover. 

It worked a treat. 

Pleased with his trick, he tried it on a variety of different objects. Unfortunately his luck ran out when he got more ambitious - and discovered that placing your foot on a balloon gives a very similar result to standing on it.