This is the sixth episode of a podcast mini-series to accompany FLOP 13 Stories of Failure, a free exhibition at the UCL Octagon Gallery open from 21 October 2019 to 10 April 2020. The exhibition has been commissioned by UCL Culture and curated by Thomas Kador (UCL Arts & Sciences). It shines a spotlight on a topic that most of us rather avoid and not talk about and investigates (through 13 stories) what happens when things go wrong. The FLOPCAST series comprises 15 different voices, all experts in their fields, discussing some of the objects on display at the exhibition to tell these stories of failure. The intention is that the podcasts can be accessed both while people are looking at the exhibits and independently without having visited the exhibition. In this sixth episode Dr Sarah Wilkes discusses the failed invention of Silly Putty.